The colonial history of the United States covers the history of European colonization of North America from the early 17th century until the incorporation of the Thirteen Colonies into the United States of America, after the War of Independence. In the late 16th century, England, France, Spain, and the Dutch Republic launched major colonization programs in North America. The death rate was very high among early immigrants, and some early attempts disappeared altogether, such as the English Lost Colony of Roanoke. Nevertheless, successful colonies were established within several decades.

European settlers came from a variety of social and religious groups, including adventurers, farmers, indentured servants, tradesmen, and a very few from the aristocracy. Settlers included the Dutch of New Netherland, the Swedes and Finns of New Sweden, the English Quakers of the Province of Pennsylvania, the English Puritans of New England, the English settlers of Jamestown, Virginia, the English Catholics and Protestant Nonconformists of the Province of Maryland, the "worthy poor" of the Province of Georgia, the Germans who settled the mid-Atlantic colonies, and the Ulster Scots of the Appalachian Mountains. These groups all became part of the United States when it gained its independence in 1776. Russian America and parts of New France and New Spain were also incorporated into the United States at later times. The diverse colonists from these various regions built colonies of distinctive social, religious, political, and economic style.

Over time, non-British colonies East of the Mississippi River were taken over and most of the inhabitants were assimilated. In Nova Scotia, however, the British expelled the French Acadians, and many relocated to Louisiana. No civil wars occurred in the Thirteen Colonies. The two chief armed rebellions were short-lived failures in Virginia in 1676 and in New York in 1689–91. Some of the colonies developed legalized systems of slavery, centered largely around the Atlantic slave trade. Wars were recurrent between the French and the British during the French and Indian Wars. By 1760, France was defeated and its colonies were seized by Britain.

On the eastern seaboard, the four distinct English regions were New England, the Middle Colonies, the Chesapeake Bay Colonies (Upper South), and the Southern Colonies (Lower South). Some historians add a fifth region of the "Frontier", which was never separately organized. A significant percentage of the native Americans living in the eastern region had been ravaged by disease before 1620, possibly introduced to them decades before by explorers and sailors (although no conclusive cause has been established).

Spanish Florida was established in 1513, when Juan Ponce de León claimed peninsular Florida for Spain during the first official European expedition to North America. This claim was enlarged as several explorers (most notably Pánfilo Narváez and Hernando de Soto) landed near Tampa Bay in the mid-1500s and wandered as far north as the Appalachian Mountains and as far west as Texas in largely unsuccessful searches for gold. The presidio of St. Augustine was founded on Florida's Atlantic coast in 1565; a series of missions were established across the Florida panhandle, Georgia, and South Carolina during the 1600s; and Pensacola was founded on the western Florida panhandle in 1698, strengthening Spanish claims to that section of the territory.

Spanish control of the Florida peninsula was much facilitated by the collapse of native cultures during the 17th century. Several Native American groups (including the Timucua, Calusa, Tequesta, Apalachee, Tocobaga, and the Ais people) had been long-established residents of Florida, and most resisted Spanish incursions onto their land. However, conflict with Spanish expeditions, raids by the Carolina colonists and their native allies, and (especially) diseases brought from Europe resulted in a drastic decline in the population of all the indigenous peoples of Florida, and large swaths of the peninsula were mostly uninhabited by the early 1700s. During the mid-1700s, small bands of Creek and other Native American refugees began moving south into Spanish Florida after having been forced off their lands by South Carolinan settlements and raids. They were later joined by African-Americans fleeing slavery in nearby colonies. These newcomers – plus perhaps a few surviving descendants of indigenous Florida peoples – eventually coalesced into a new Seminole culture.

France began colonizing the Americas in the 16th century and continued on into the following centuries as it established a colonial empire in the Western Hemisphere. France established colonies in much of eastern North America, on a number of Caribbean islands, and in South America. Most colonies were developed to export products such as fish, rice, sugar, and furs. The first French colonial empire stretched to over 10,000,000 km2 at its peak in 1710, which was the second largest colonial empire in the world, after the Spanish Empire.As they colonized the New World, the French established forts and settlements that would become such cities as Quebec and Montreal in Canada; Detroit, Green Bay, St. Louis, Cape Girardeau, Mobile, Biloxi, Baton Rouge and New Orleans in the United States; and Port-au-Prince, Cap-Haïtien (founded as Cap-Français) in Haiti, Cayenne in French Guiana and São Luís (founded as Saint-Louis de Maragnan) in Brazil.

Slavery in the colonial history of the United States, from 1526 to 1776, developed from complex factors, and researchers have proposed several theories to explain the development of the institution of slavery and of the slave trade. Slavery strongly correlated with the European colonies' demand for labor, especially for the labor-intensive plantation economies of the sugar colonies in the Caribbean and South America, operated by Great Britain, France, Spain, Portugal, and the Dutch Republic.

Slave-ships of the Atlantic slave trade transported captives for slavery from Africa to the Americas. Indigenous people were also enslaved in the North American colonies, but on a smaller scale, and Indian slavery largely ended in the late eighteenth century. Enslavement of Indigenous people did continue to occur in the Southern states until the Emancipation Proclamation issued by President Abraham Lincoln in 1863. Slavery was also used as a punishment for crimes committed by free people. In the colonies, slave status for Africans became hereditary with the adoption and application of civil law into colonial law, which defined the status of children born in the colonies as determined by the mother - known as partus sequitur ventrem. Children born to enslaved women were born enslaved, regardless of paternity. Children born to free women were free, regardless of ethnicity. By the time of the American Revolution, the European colonial powers had embedded chattel slavery for Africans and their descendants throughout the Americas, including the future United States.

In 1602, the Republic of the Seven United Netherlands chartered a young and eager Dutch East India Company (Vereenigde Oostindische Compagnie or "VOC") with the mission of exploring North America's rivers and bays for a direct passage through to the Indies. Along the way, Dutch explorers were charged to claim any uncharted areas for the United Provinces, which led to several significant expeditions and, over time, Dutch explorers founded the province of New Netherland. By 1610, the VOC had already commissioned English explorer Henry Hudson who, in an attempt to find the Northwest Passage to the Indies, discovered and claimed for the VOC parts of the present-day United States and Canada. Hudson entered the Upper New York Bay by sailboat, heading up the Hudson River, which now bears his name.

Like the French in the north, the Dutch focused their interest on the fur trade. To that end, they cultivated contingent relations with the Five Nations of the Iroquois to procure greater access to key central regions from which the skins came.

The Dutch encouraged a kind of feudal aristocracy over time, to attract settlers to the region of the Hudson River, in what became known as the system of the Charter of Freedoms and Exemptions. Further south, a Swedish trading company that had ties with the Dutch tried to establish its first settlement along the Delaware River three years later. Without resources to consolidate its position, New Sweden was gradually absorbed by New Holland and later in Pennsylvania and Delaware.

The earliest Dutch settlement was built around 1613, and consisted of a number of small huts built by the crew of the "Tijger" (Tiger), a Dutch ship under the command of Captain Adriaen Block, which had caught fire while sailing on the Hudson. Soon after, the first of two Fort Nassaus was built, and small factorijen or trading posts went up, where commerce could be conducted with the Algonquian and Iroquois population, possibly at Schenectady, Esopus, Quinnipiac, Communipaw, and elsewhere.

The British colonization of the Americas was the history of establishment of control, settlement, and colonization of the continents of the Americas by England, Scotland and, after 1707, Great Britain. Colonization efforts began in the late 16th century with failed attempts by England to establish permanent colonies in the North. The first permanent English colony was established in Jamestown, Virginia in 1607. Approximately 30,000 Algonquian peoples lived in the region at the time. Over the next several centuries more colonies were established in North America, Central America, South America, and the Caribbean. Though most British colonies in the Americas eventually gained independence, some colonies have opted to remain under Britain's jurisdiction as British Overseas Territories.

The Puritan migration to New England was marked in its effects from 1620 to 1640, declining sharply afterwards. The term Great Migration usually refers to the migration in the period of English Puritans to Massachusetts and the Caribbean, especially Barbados. They came in family groups rather than as isolated individuals and were mainly motivated for freedom to practice their beliefs.

New Sweden was a Swedish colony along the lower reaches of the Delaware River in the United States from 1638 to 1655, established during the Thirty Years' War when Sweden was a great military power. New Sweden formed part of the Swedish efforts to colonize the Americas. Settlements were established on both sides of the Delaware Valley in the region of Delaware, New Jersey, Maryland, and Pennsylvania, often in places where Swedish traders had been visiting since about 1610. Fort Christina in Wilmington, Delaware, was the first settlement, named after the reigning Swedish monarch. The settlers were Swedes, Finns, and a number of Dutch. New Sweden was conquered by the Dutch Republic in 1655 during the Second Northern War and incorporated into the Dutch colony of New Netherland.

The French and Indian War (1754–1763) was a theater of the Seven Years' War, which pitted the North American colonies of the British Empire against those of the French, each side being supported by various Native American tribes. At the start of the war, the French colonies had a population of roughly 60,000 settlers, compared with 2 million in the British colonies. The outnumbered French particularly depended on their native allies.

Two years into the French and Indian War, in 1756, Great Britain declared war on France, beginning the worldwide Seven Years' War. Many view the French and Indian War as being merely the American theater of this conflict.

The American Revolution was an ideological and political revolution that occurred in British America between 1765 and 1791. The Americans in the Thirteen Colonies formed independent states that defeated the British in the American Revolutionary War (1775–1783), gaining independence from the British Crown, establishing the constitution that created the United States of America, the first modern constitutional liberal democracy.

The Cherokee–American wars, also known as the Chickamauga Wars, were a series of raids, campaigns, ambushes, minor skirmishes, and several full-scale frontier battles in the Old Southwest from 1776 to 1794 between the Cherokee and American settlers on the frontier. Most of the events took place in the Upper South region. While the fighting stretched across the entire period, there were extended periods with little or no action.

The Cherokee leader Dragging Canoe, whom some historians call "the Savage Napoleon", and his warriors, and other Cherokee fought alongside and together with warriors from several other tribes, most often the Muscogee in the Old Southwest and the Shawnee in the Old Northwest. During the Revolutionary War, they also fought alongside British troops, Loyalist militia, and the King's Carolina Rangers against the rebel colonists, hoping to expel them from their territory.

Open warfare broke out in the summer of 1776 in the Overmountain settlements of the Washington District, mainly those along the Watauga, Holston, Nolichucky, and Doe rivers in East Tennessee, as well as the colonies (later states) of Virginia, North Carolina, South Carolina, and Georgia. It later spread to settlements along the Cumberland River in Middle Tennessee and in Kentucky.

The wars can be divided into two phases. The first phase took place from 1776 to 1783, in which the Cherokee fought as allies of the Kingdom of Great Britain against the American colonies. The Cherokee War of 1776 encompassed the entirety of the Cherokee nation. At the end of 1776, the only militant Cherokee were those who migrated with Dragging Canoe to the Chickamauga towns and became known as the "Chickamauga Cherokee". The second phase lasted from 1783 to 1794. The Cherokee served as proxies of the Viceroyalty of New Spain against the recently formed United States of America. Because they migrated westward to new settlements initially known as the "Five Lower Towns", referring to their location in the Piedmont, these people became known as the Lower Cherokee. This term was used well into the 19th century. The Chickamauga ended their warfare in November 1794 with the Treaty of Tellico Blockhouse.

In 1786, Mohawk leader Joseph Brant, a major war chief of the Iroquois, had organized the Western Confederacy of tribes to resist American settlement in Ohio Country. The Lower Cherokee were founding members and fought in the Northwest Indian War that resulted from this conflict. The Northwest Indian War ended with the Treaty of Greenville in 1795.

The conclusion of the Indian wars enabled the settlement of what had been called "Indian territory" in the Royal Proclamation of 1763, and culminated in the first trans-Appalachian states, Kentucky in 1792 and Ohio in 1803.

The Confederation period was the era of United States history in the 1780s after the American Revolution and prior to the ratification of the United States Constitution. In 1781, the United States ratified the Articles of Confederation and Perpetual Union and prevailed in the Battle of Yorktown, the last major land battle between British and American Continental forces in the American Revolutionary War. American independence was confirmed with the 1783 signing of the Treaty of Paris. The fledgling United States faced several challenges, many of which stemmed from the lack of a strong national government and unified political culture. The period ended in 1789 following the ratification of the United States Constitution, which established a new, more powerful, national government.

The Northwest Indian War (1786–1795), also known by other names, was an armed conflict for control of the Northwest Territory fought between the United States and a united group of Native American nations known today as the Northwestern Confederacy. The United States Army considers it the first of the American Indian Wars.

Following centuries of conflict for control of this region, it was granted to the new United States by the Kingdom of Great Britain in article 2 of the Treaty of Paris, which ended the American Revolutionary War. The treaty used the Great Lakes as a border between British territory and the United States. This granted significant territory to the United States, initially known as the Ohio Country and the Illinois Country, which had previously been prohibited to new settlements. However, numerous Native American peoples inhabited this region, and the British maintained a military presence and continued policies that supported their Native allies. With the encroachment of European-American settlers west of the Appalachian Mountains after the war, a Huron-led confederacy formed in 1785 to resist the usurpation of Indian lands, declaring that lands north and west of the Ohio River were Indian territory.

Four years after the start of the British-supported Native American military campaign, the Constitution of the United States went into effect; George Washington was sworn in as president, which made him the commander-in-chief of U.S. military forces. Accordingly, Washington directed the United States Army to enforce U.S. sovereignty over the territory. The U.S. Army, consisting mostly of untrained recruits and volunteer militiamen, suffered a series of major defeats, including the Harmar campaign (1790) and St. Clair's defeat (1791), which are among the worst defeats ever suffered in the history of the U.S. Army.

St. Clair's devastating loss destroyed most of the United States Army and left the United States vulnerable. Washington was also under congressional investigation and was compelled to quickly raise a bigger army. He chose Revolutionary War veteran General Anthony Wayne to organize and train a proper fighting force. Wayne took command of the new Legion of the United States late in 1792 and spent a year building, training, and acquiring supplies. After a methodical campaign up the Great Miami and Maumee river valleys in western Ohio Country, Wayne led his Legion to a decisive victory at the Battle of Fallen Timbers near the southwestern shore of Lake Erie (near modern Toledo, Ohio) in 1794. Afterward, he went on to establish Fort Wayne at the Miami capital of Kekionga, the symbol of U.S. sovereignty in the heart of Indian Country and within sight of the British. The defeated tribes were forced to cede extensive territory, including much of present-day Ohio, in the Treaty of Greenville in 1795. The Jay Treaty in the same year arranged for cessions of British Great Lakes outposts on the U.S. territory. The British would later retake this land briefly during the War of 1812.

The Federalist Era in American history ran from 1788 to 1800, a time when the Federalist Party and its predecessors were dominant in American politics. During this period, Federalists generally controlled Congress and enjoyed the support of President George Washington and President John Adams. The era saw the creation of a new, stronger federal government under the United States Constitution, a deepening of support for nationalism, and diminished fears of tyranny by a central government. The era began with the ratification of the United States Constitution and ended with the Democratic-Republican Party's victory in the 1800 elections.

The Second Great Awakening was a Protestant religious revival during the early 19th century in the United States. The Second Great Awakening, which spread religion through revivals and emotional preaching, sparked a number of reform movements. Revivals were a key part of the movement and attracted hundreds of converts to new Protestant denominations. The Methodist Church used circuit riders to reach people in frontier locations. The Second Great Awakening led to a period of antebellum social reform and an emphasis on salvation by institutions. The outpouring of religious fervor and revival began in Kentucky and Tennessee in the 1790s and early 1800s among the Presbyterians, Methodists and Baptists.

Historians named the Second Great Awakening in the context of the First Great Awakening of the 1730s and 1750s and of the Third Great Awakening of the late 1850s to early 1900s. The First Awakening was part of a much larger Romantic religious movement that was sweeping across England, Scotland, and Germany. New religious movements emerged during the Second Great Awakening, such as Adventism, Dispensationalism, and the Latter Day Saint movement.

Jeffersonian democracy, named after its advocate Thomas Jefferson, was one of two dominant political outlooks and movements in the United States from the 1790s to the 1820s. The Jeffersonians were deeply committed to American republicanism, which meant opposition to what they considered to be artificial aristocracy, opposition to corruption, and insistence on virtue, with a priority for the "yeoman farmer", "planters", and the "plain folk". They were antagonistic to the aristocratic elitism of merchants, bankers, and manufacturers, distrusted factory workers, and were on the watch for supporters of the Westminster system.

The term was commonly used to refer to the Democratic-Republican Party (formally named the "Republican Party"), which Jefferson founded in opposition to the Federalist Party of Alexander Hamilton. At the beginning of the Jeffersonian era, only two states (Vermont and Kentucky) had established universal white male suffrage by abolishing property requirements. By the end of the period, more than half of the states had followed suit, including virtually all of the states in the Old Northwest. States then also moved on to allowing white male popular votes for presidential elections, canvassing voters in a more modern style. Jefferson's party, known today as the Democratic–Republican Party, was then in full control of the apparatus of government – from the state legislature and city hall to the White House.

The Louisiana Purchase was the acquisition of the territory of Louisiana by the United States from the French First Republic in 1803. In return for fifteen million dollars, or approximately eighteen dollars per square mile, the United States nominally acquired a total of 828,000 sq mi (2,140,000 km2; 530,000,000 acres). However, France only controlled a small fraction of this area, most of it inhabited by Native Americans; for the majority of the area, what the United States bought was the "preemptive" right to obtain "Indian" lands by treaty or by conquest, to the exclusion of other colonial powers. The total cost of all subsequent treaties and financial settlements over the land has been estimated to be around 2.6 billion dollars.

The Kingdom of France had controlled the Louisiana territory from 1699 until it was ceded to Spain in 1762. In 1800, Napoleon, the First Consul of the French Republic, regained ownership of Louisiana as part of a broader project to re-establish a French colonial empire in North America. However, France's failure to put down a revolt in Saint-Domingue, coupled with the prospect of renewed warfare with the United Kingdom, prompted Napoleon to consider selling Louisiana to the United States. Acquisition of Louisiana was a long-term goal of President Thomas Jefferson, who was especially eager to gain control of the crucial Mississippi River port of New Orleans. Jefferson tasked James Monroe and Robert R. Livingston with purchasing New Orleans. Negotiating with French Treasury Minister François Barbé-Marbois (who was acting on behalf of Napoleon), the American representatives quickly agreed to purchase the entire territory of Louisiana after it was offered. Overcoming the opposition of the Federalist Party, Jefferson and Secretary of State James Madison persuaded Congress to ratify and fund the Louisiana Purchase.

The Louisiana Purchase extended United States sovereignty across the Mississippi River, nearly doubling the nominal size of the country. At the time of the purchase, the territory of Louisiana's non-native population was around 60,000 inhabitants, of whom half were enslaved Africans. The western borders of the purchase were later settled by the 1819 Adams–Onís Treaty with Spain, while the northern borders of the purchase were adjusted by the Treaty of 1818 with Britain.

The War of 1812 was fought by the United States of America and its indigenous allies against the United Kingdom and its allies in British North America, with limited participation by Spain in Florida. It began when the US declared war on 18 June 1812 and, although peace terms were agreed upon in the December 1814 Treaty of Ghent, did not officially end until the peace treaty was ratified by Congress on 17 February 1815.

The Seminole Wars (also known as the Florida Wars) were a series of three military conflicts between the United States and the Seminoles that took place in Florida between about 1816 and 1858. The Seminoles are a Native American nation which coalesced in northern Florida during the early 1700s, when the territory was still a Spanish colonial possession. Tensions grew between the Seminoles and settlers in the newly independent United States in the early 1800s, mainly because enslaved people regularly fled from Georgia into Spanish Florida, prompting slaveowners to conduct slave raids across the border. A series of cross-border skirmishes escalated into the First Seminole War in 1817, when General Andrew Jackson led an incursion into the territory over Spanish objections. Jackson's forces destroyed several Seminole and Black Seminole towns and briefly occupied Pensacola before withdrawing in 1818. The U.S. and Spain soon negotiated the transfer of the territory with the Adams-Onis Treaty of 1819.

The United States gained possession of Florida in 1821 and coerced the Seminoles into leaving their lands in the Florida panhandle for a large Indian reservation in the center of the peninsula per the Treaty of Moultrie Creek. About ten years later, however, the US government under President Andrew Jackson demanded that they leave Florida altogether and relocate to Indian Territory per the Indian Removal Act. A few bands reluctantly complied but most resisted violently, leading to the Second Seminole War (1835-1842), which was by far the longest and most wide-ranging of the three conflicts. Initially, less than 2000 Seminole warriors employed hit-and-run guerilla warfare tactics and knowledge of the land to evade and frustrate a combined U.S. Army and Marine force that grew to over 30,000. Instead of continuing to pursue these small bands, American commanders eventually changed their strategy and focused on seeking out and destroying hidden Seminole villages and crops, putting increasing pressure on resisters to surrender or starve with their families.

Most of the Seminole population had been relocated to Indian Country or killed by the mid-1840s, though several hundred settled in southwest Florida, where they were allowed to remain in an uneasy truce. Tensions over the growth of nearby Fort Myers led to renewed hostilities, and the Third Seminole War broke out in 1855. By the cessation of active fighting in 1858, the few remaining bands of Seminoles in Florida had fled deep into the Everglades to land unwanted by white settlers. Taken together, the Seminole Wars were the longest, most expensive, and most deadly of all American Indian Wars.

The Era of Good Feelings marked a period in the political history of the United States that reflected a sense of national purpose and a desire for unity among Americans in the aftermath of the War of 1812. The era saw the collapse of the Federalist Party and an end to the bitter partisan disputes between it and the dominant Democratic-Republican Party during the First Party System. President James Monroe strove to downplay partisan affiliation in making his nominations, with the ultimate goal of national unity and eliminating political parties altogether from national politics. The period is so closely associated with Monroe's presidency (1817–1825) and his administrative goals that his name and the era are virtually synonymous.

The Monroe Doctrine was a United States foreign policy position that opposed European colonialism in the Western Hemisphere. It held that any intervention in the political affairs of the Americas by foreign powers was a potentially hostile act against the United States. The doctrine was central to American foreign policy for much of the 19th and early 20th centuries.

President James Monroe first articulated the doctrine on December 2, 1823, during his seventh annual State of the Union Address to Congress (though it would not be named after him until 1850). At the time, nearly all Spanish colonies in the Americas had either achieved or were close to independence. Monroe asserted that the New World and the Old World were to remain distinctly separate spheres of influence, and thus further efforts by European powers to control or influence sovereign states in the region would be viewed as a threat to U.S. security. In turn, the United States would recognize and not interfere with existing European colonies nor meddle in the internal affairs of European countries.

Because the U.S. lacked both a credible navy and army at the time of the doctrine's proclamation, it was largely disregarded by the colonial powers. While it was successfully enforced in part by the United Kingdom, who used it as an opportunity to enforce its own Pax Britannica policy, the doctrine was still broken several times over the course of the 19th century. By the turn of the 20th century, however, the United States itself was able to successfully enforce the doctrine, and it became seen as a defining moment in the foreign policy of the United States and one of its longest-standing tenets. The intent and effect of the doctrine persisted for over a century after that, with only small variations, and would be invoked by many American statesmen and several American presidents, including Ulysses S. Grant, Theodore Roosevelt, John F. Kennedy, and Ronald Reagan.

After 1898, the Monroe Doctrine was reinterpreted by Latin American lawyers and intellectuals as promoting multilateralism and non-intervention. In 1933, under President Franklin D. Roosevelt, the United States affirmed this new interpretation, namely through co-founding the Organization of American States. Into the 21st century, the doctrine continues to be variably denounced, reinstated, or reinterpreted.

Jacksonian democracy was a 19th-century political philosophy in the United States that expanded suffrage to most white men over the age of 21, and restructured a number of federal institutions. Originating with the seventh U.S. president, Andrew Jackson and his supporters, it became the nation's dominant political worldview for a generation. The term itself was in active use by the 1830s.

This era, called the Jacksonian Era or Second Party System by historians and political scientists, lasted roughly from Jackson's 1828 election as president until slavery became the dominant issue with the passage of the Kansas–Nebraska Act in 1854 and the political repercussions of the American Civil War dramatically reshaped American politics. It emerged when the long-dominant Democratic-Republican Party became factionalized around the 1824 United States presidential election. Jackson's supporters began to form the modern Democratic Party. His political rivals John Quincy Adams and Henry Clay created the National Republican Party, which would afterward combine with other anti-Jackson political groups to form the Whig Party.

Broadly speaking, the era was characterized by a democratic spirit. It built upon Jackson's equal political policy, subsequent to ending what he termed a monopoly of government by elites. Even before the Jacksonian era began, suffrage had been extended to a majority of white male adult citizens, a result which the Jacksonians celebrated. Jacksonian democracy also promoted the strength of the presidency and the executive branch at the expense of the United States Congress, while also seeking to broaden the public's participation in government. The Jacksonians demanded elected, not appointed, judges and rewrote many state constitutions to reflect the new values. In national terms, they favored geographical expansionism, justifying it in terms of manifest destiny. There was usually a consensus among both Jacksonians and Whigs that battles over slavery should be avoided.

Jackson's expansion of democracy was largely limited to European Americans, and voting rights were extended to adult white males only. There was little or no change, and in many cases a reduction of the rights of African Americans and Native Americans during the extensive period of Jacksonian democracy, spanning from 1829 to 1860.

The Trail of Tears was a series of forced displacements of approximately 60,000 American Indians of the "Five Civilized Tribes" between 1830 and 1850 by the United States government. Part of the Indian removal, the ethnic cleansing was gradual, occurring over a period of nearly two decades. Members of the so-called "Five Civilized Tribes"—the Cherokee, Muscogee (Creek), Seminole, Chickasaw, and Choctaw nations (including thousands of their black slaves)—were forcibly removed from their ancestral homelands in the Southeastern United States to areas to the west of the Mississippi River that had been designated Indian Territory. The forced relocations were carried out by government authorities after the passage of the Indian Removal Act in 1830. The Cherokee removal in 1838 (the last forced removal east of the Mississippi) was brought on by the discovery of gold near Dahlonega, Georgia, in 1828, resulting in the Georgia Gold Rush.

The relocated peoples suffered from exposure, disease, and starvation while en route to their newly designated Indian reserve. Thousands died from disease before reaching their destinations or shortly after. According to Native American activist Suzan Shown Harjo of the Smithsonian's National Museum of the American Indian, the event constituted a genocide, although this label has been rejected by historian Gary Clayton Anderson.

The Indian Removal Act was signed into law on May 28, 1830, by United States President Andrew Jackson. The law, as described by Congress, provided "for an exchange of lands with the Indians residing in any of the states or territories, and for their removal west of the river Mississippi." During the Presidency of Jackson (1829-1837) and his successor Martin Van Buren (1837-1841) more than 60,000 Indians from at least 18 tribes were forced to move west of the Mississippi River where they were allocated new lands. The southern tribes were resettled mostly in Indian Territory (Oklahoma). The northern tribes were resettled initially in Kansas. With a few exceptions the United States east of the Mississippi and south of the Great Lakes was emptied of its Indian population. The movement westward of the Indian tribes was characterized by a large number of deaths occasioned by the hardships of the journey.

The U.S. Congress approved the Act by a narrow majority in the House of Representatives. The Indian Removal Act was supported by President Jackson, southern and white settlers, and several state governments, especially that of Georgia. Indian tribes, the Whig Party, and many Americans opposed the bill. Legal efforts to allow Indian tribes to remain on their land in the eastern U.S. failed. Most famously, the Cherokee (excluding the Treaty Party) challenged their relocation, but were unsuccessful in the courts; they were forcibly removed by the United States government in a march to the west that later became known as the Trail of Tears.

The Oregon Trail was a 2,170-mile (3,490 km) east–west, large-wheeled wagon route and emigrant trail in the United States that connected the Missouri River to valleys in Oregon. The eastern part of the Oregon Trail spanned part of what is now the state of Kansas and nearly all of what are now the states of Nebraska and Wyoming. The western half of the trail spanned most of the current states of Idaho and Oregon.

The Oregon Trail was laid by fur traders and trappers from about 1811 to 1840 and was only passable on foot or on horseback. By 1836, when the first migrant wagon train was organized in Independence, Missouri, a wagon trail had been cleared to Fort Hall, Idaho. Wagon trails were cleared increasingly farther west and eventually reached all the way to the Willamette Valley in Oregon, at which point what came to be called the Oregon Trail was complete, even as almost annual improvements were made in the form of bridges, cutoffs, ferries, and roads, which made the trip faster and safer. From various starting points in Iowa, Missouri, or Nebraska Territory, the routes converged along the lower Platte River Valley near Fort Kearny, Nebraska Territory, and led to fertile farmlands west of the Rocky Mountains.

From the early to mid-1830s (and particularly through the years 1846–1869) the Oregon Trail and its many offshoots were used by about 400,000 settlers, farmers, miners, ranchers, and business owners and their families. The eastern half of the trail was also used by travelers on the California Trail (from 1843), Mormon Trail (from 1847), and Bozeman Trail (from 1863) before turning off to their separate destinations. Use of the trail declined after the first transcontinental railroad was completed in 1869, making the trip west substantially faster, cheaper, and safer. Today, modern highways, such as Interstate 80 and Interstate 84, follow parts of the same course westward and pass through towns originally established to serve those using the Oregon Trail.

The Republic of Texas declared independence from the Republic of Mexico on March 2, 1836. It applied for annexation to the United States the same year, but was rejected by the Secretary of State. At the time, the vast majority of the Texian population favored the annexation of the Republic by the United States. The leadership of both major U.S. political parties, the Democrats and the Whigs, opposed the introduction of Texas, a vast slave-holding region, into the volatile political climate of the pro- and anti-slavery sectional controversies in Congress. Moreover, they wished to avoid a war with Mexico, whose government had outlawed slavery and refused to acknowledge the sovereignty of its rebellious northern province. With Texas's economic fortunes declining by the early 1840s, the President of the Texas Republic, Sam Houston, arranged talks with Mexico to explore the possibility of securing official recognition of independence, with the United Kingdom mediating.

In 1843, U.S. President John Tyler, then unaligned with any political party, decided independently to pursue the annexation of Texas in a bid to gain a base of support for another four years in office. His official motivation was to outmaneuver suspected diplomatic efforts by the British government for the emancipation of slaves in Texas, which would undermine slavery in the United States. Through secret negotiations with the Houston administration, Tyler secured a treaty of annexation in April 1844. When the documents were submitted to the U.S. Senate for ratification, the details of the terms of annexation became public and the question of acquiring Texas took center stage in the presidential election of 1844. Pro-Texas-annexation southern Democratic delegates denied their anti-annexation leader Martin Van Buren the nomination at their party's convention in May 1844. In alliance with pro-expansion northern Democratic colleagues, they secured the nomination of James K. Polk, who ran on a pro-Texas Manifest Destiny platform.

On March 1, 1845, President Tyler signed the annexation bill, and on March 3 (his last full day in office), he forwarded the House version to Texas, offering immediate annexation (which preempted Polk). When Polk took office at noon EST the next day, he encouraged Texas to accept the Tyler offer. Texas ratified the agreement with popular approval from Texans. The bill was signed by President Polk on December 29, 1845, accepting Texas as the 28th state of the Union. Texas formally joined the union on February 19, 1846. Following the annexation, relations between the United States and Mexico deteriorated because of an unresolved dispute over the border between Texas and Mexico, and the Mexican–American War broke out only a few months later.

The California genocide was the killing of thousands of indigenous peoples of California by United States government agents and private citizens in the 19th century. It began following the American Conquest of California from Mexico, and the influx of settlers due to the California Gold Rush, which accelerated the decline of the indigenous population of California. Between 1846 and 1873, it is estimated that non-Natives killed between 9,492 and 16,094 California Natives. Hundreds to thousands were additionally starved or worked to death. Acts of enslavement, kidnapping, rape, child separation and displacement were widespread. These acts were encouraged, tolerated, and carried out by state authorities and militias.

The 1925 book Handbook of the Indians of California estimated that the indigenous population of California decreased from perhaps as many as 150,000 in 1848 to 30,000 in 1870 and fell further to 16,000 in 1900. The decline was caused by disease, low birth rates, starvation, killings, and massacres. California Natives, particularly during the Gold Rush, were targeted in killings. Between 10,000 and 27,000 were also taken as forced labor by settlers. The state of California used its institutions to favor white settlers' rights over indigenous rights, dispossessing natives.

Since the 2000s several American academics and activist organizations, both Native American and European American, have characterized the period immediately following the U.S. Conquest of California as one in which the state and federal governments waged genocide against the Native Americans in the territory. In 2019, California's governor Gavin Newsom apologized for the genocide and called for a research group to be formed to better understand the topic and inform future generations.

The Mexican–American War was an armed conflict between the United States and Mexico from 1846 to 1848. It followed the 1845 U.S. annexation of Texas, which Mexico considered Mexican territory because it did not recognize the Velasco treaty signed by Mexican General Antonio López de Santa Anna when he was a prisoner of the Texian Army during the 1836 Texas Revolution. The Republic of Texas was de facto an independent country, but most of its citizens wished to be annexed by the United States. Domestic sectional politics in the U.S. were preventing annexation since Texas would have been a slave state, upsetting the balance of power between Northern free states and Southern slave states. In the 1844 United States presidential election, Democrat James K. Polk was elected on a platform of expanding U.S. territory in Oregon and Texas. Polk advocated expansion by either peaceful means or armed force, with the 1845 annexation of Texas furthering that goal by peaceful means. However, the boundary between Texas and Mexico was disputed, with the Republic of Texas and the U.S. asserting it to be the Rio Grande and Mexico claiming it to be the more-northern Nueces River. Both Mexico and the U.S. claimed the disputed area and sent troops. Polk sent U.S. Army troops to the area; he also sent a diplomatic mission to Mexico to try to negotiate the sale of territory. Mexican forces attacked U.S. forces, and the United States Congress declared war.

The California Gold Rush (1848–1855) was a gold rush that began on January 24, 1848, when gold was found by James W. Marshall at Sutter's Mill in Coloma, California. The news of gold brought approximately 300,000 people to California from the rest of the United States and abroad. The sudden influx of gold into the money supply reinvigorated the American economy; the sudden population increase allowed California to go rapidly to statehood, in the Compromise of 1850. The Gold Rush had severe effects on Native Californians and accelerated the Native American population's decline from disease, starvation and the California genocide.

The effects of the Gold Rush were substantial. Whole indigenous societies were attacked and pushed off their lands by the gold-seekers, called "forty-niners" (referring to 1849, the peak year for Gold Rush immigration). Outside of California, the first to arrive were from Oregon, the Sandwich Islands (Hawaii) and Latin America in late 1848. Of the approximately 300,000 people who came to California during the Gold Rush, about half arrived by sea and half came overland on the California Trail and the Gila River trail; forty-niners often faced substantial hardships on the trip. While most of the newly arrived were Americans, the gold rush attracted thousands from Latin America, Europe, Australia and China. Agriculture and ranching expanded throughout the state to meet the needs of the settlers. San Francisco grew from a small settlement of about 200 residents in 1846 to a boomtown of about 36,000 by 1852. Roads, churches, schools and other towns were built throughout California. In 1849 a state constitution was written. The new constitution was adopted by referendum vote; the future state's interim first governor and legislature were chosen. In September 1850, California became a state.

At the beginning of the Gold Rush, there was no law regarding property rights in the goldfields and a system of "staking claims" was developed. Prospectors retrieved the gold from streams and riverbeds using simple techniques, such as panning. Although mining caused environmental harm, more sophisticated methods of gold recovery were developed and later adopted around the world. New methods of transportation developed as steamships came into regular service. By 1869, railroads were built from California to the eastern United States. At its peak, technological advances reached a point where significant financing was required, increasing the proportion of gold companies to individual miners. Gold worth tens of billions of today's US dollars was recovered, which led to great wealth for a few, though many who participated in the California Gold Rush earned little more than they had started with.

The women's suffrage movement began with the June 1848 National Convention of the Liberty Party. Presidential candidate Gerrit Smith argued for and established women's suffrage as a party plank. One month later, his cousin Elizabeth Cady Stanton joined with Lucretia Mott and other women to organize the Seneca Falls Convention, featuring the Declaration of Sentiments demanding equal rights for women, and the right to vote. Many of these activists became politically aware during the abolitionist movement. The women's rights campaign during "first-wave feminism" was led by Stanton, Lucy Stone and Susan B. Anthony, among many others. Stone and Paulina Wright Davis organized the prominent and influential National Women's Rights Convention in 1850.

The movement reorganized after the Civil War, gaining experienced campaigners, many of whom had worked for prohibition in the Women's Christian Temperance Union. By the end of the 19th century a few western states had granted women full voting rights, though women had made significant legal victories, gaining rights in areas such as property and child custody.

The Compromise of 1850 was a package of five separate bills passed by the United States Congress in September 1850 that temporarily defused tensions between slave and free states in the years leading up to the American Civil War. Designed by Whig senator Henry Clay and Democratic senator Stephen A. Douglas, with the support of President Millard Fillmore, the compromise centered around how to handle slavery in recently acquired territories from the Mexican–American War (1846-48).

The component acts:

• approved California’s request to enter the Union as a free state
• strengthened fugitive slave laws with the Fugitive Slave Act of 1850
• banned the slave trade in Washington, D.C. (while still allowing slavery itself there)
• defined northern and western borders for Texas while establishing a territorial government for the Territory of New Mexico, with no restrictions on whether any future state from this territory would be free or slave
• established a territorial government for the Territory of Utah, with no restrictions on whether any future state from this territory would be free or slave

A debate over slavery in the territories had erupted during the Mexican–American War, as many Southerners sought to expand slavery to the newly-acquired lands and many Northerners opposed any such expansion. The debate was further complicated by Texas's claim to all former Mexican territory north and east of the Rio Grande, including areas it had never effectively controlled. The debates over the bill were the most famous in Congressional history, and the divisions devolved into fistfights and drawn guns on the floor of Congress.

Under the compromise, Texas surrendered its claims to present-day New Mexico and other states in return for federal assumption of Texas's public debt. California was admitted as a free state, while the remaining portions of the Mexican Cession were organized into New Mexico Territory and Utah Territory. Under the concept of popular sovereignty, the people of each territory would decide whether or not slavery would be permitted. The compromise also included a more stringent Fugitive Slave Law and banned the slave trade in Washington, D.C. The issue of slavery in the territories would be re-opened by the Kansas–Nebraska Act (1854), but the Compromise of 1850 played a major role in postponing the American Civil War.

Dred Scott v. Sandford was a landmark decision of the United States Supreme Court that held the U.S. Constitution did not extend American citizenship to people of black African descent, and thus they could not enjoy the rights and privileges the Constitution conferred upon American citizens. The Supreme Court's decision has been widely denounced, both for its overt racism and for its crucial role in the start of the American Civil War four years later. Legal scholar Bernard Schwartz said that it "stands first in any list of the worst Supreme Court decisions". Chief Justice Charles Evans Hughes called it the Court's "greatest self-inflicted wound".

The decision involved the case of Dred Scott, an enslaved black man whose owners had taken him from Missouri, a slave-holding state, into Illinois and the Wisconsin Territory, where slavery was illegal. When his owners later brought him back to Missouri, Scott sued for his freedom and claimed that because he had been taken into "free" U.S. territory, he had automatically been freed and was legally no longer a slave. Scott sued first in Missouri state court, which ruled that he was still a slave under its law. He then sued in U.S. federal court, which ruled against him by deciding that it had to apply Missouri law to the case. He then appealed to the U.S. Supreme Court.

In March 1857, the Supreme Court issued a 7–2 decision against Scott. In an opinion written by Chief Justice Roger Taney, the Court ruled that people of African descent "are not included, and were not intended to be included, under the word 'citizens' in the Constitution, and can therefore claim none of the rights and privileges which that instrument provides for and secures to citizens of the United States". Taney supported his ruling with an extended survey of American state and local laws from the time of the Constitution's drafting in 1787 that purported to show that a "perpetual and impassable barrier was intended to be erected between the white race and the one which they had reduced to slavery". Because the Court ruled that Scott was not an American citizen, he was also not a citizen of any state and, accordingly, could never establish the "diversity of citizenship" that Article III of the U.S. Constitution requires for a U.S. federal court to be able to exercise jurisdiction over a case. After ruling on those issues surrounding Scott, Taney struck down the Missouri Compromise as a limitation on slave owners' property rights that exceeded the U.S. Congress's constitutional powers.

The American Civil War (April 12, 1861 – May 9, 1865; also known by other names) was a civil war in the United States between the Union (states that remained loyal to the federal union, or "the North") and the Confederacy (states that voted to secede, or "the South"). The central cause of the war was the status of slavery, especially the expansion of slavery into territories acquired as a result of the Louisiana Purchase and the Mexican–American War. On the eve of the Civil War in 1860, four million of the 32 million Americans (~13%) were enslaved black people, almost all in the South.

The Civil War is one of the most studied and written about episodes in the history of the United States. It remains the subject of cultural and historiographical debate. Of particular interest is the persisting myth of the Lost Cause of the Confederacy. The American Civil War was among the earliest to use industrial warfare. Railroads, the telegraph, steamships, the ironclad warship, and mass-produced weapons saw wide use. In total the war left between 620,000 and 750,000 soldiers dead, along with an undetermined number of civilian casualties. The Civil War remains the deadliest military conflict in American history. The technology and brutality of the Civil War foreshadowed the coming World Wars.

The Emancipation Proclamation, officially Proclamation 95, was a presidential proclamation and executive order issued by United States President Abraham Lincoln on January 1, 1863, during the American Civil War. The Proclamation changed the legal status of more than 3.5 million enslaved African Americans in the secessionist Confederate states from enslaved to free. As soon as slaves escaped the control of their enslavers, either by fleeing to Union lines or through the advance of federal troops, they were permanently free. In addition, the Proclamation allowed for former slaves to "be received into the armed service of the United States."

The Emancipation Proclamation was never challenged in court. To ensure the abolition of slavery in all of the U.S., Lincoln also insisted that Reconstruction plans for Southern states require them to enact laws abolishing slavery (which occurred during the war in Tennessee, Arkansas, and Louisiana); Lincoln encouraged border states to adopt abolition (which occurred during the war in Maryland, Missouri, and West Virginia) and pushed for passage of the 13th Amendment. The Senate passed the 13th Amendment by the necessary two-thirds vote on April 8, 1864; the House of Representatives did so on January 31, 1865; and the required three-fourths of the states ratified it on December 6, 1865. The amendment made slavery and involuntary servitude unconstitutional, "except as a punishment for crime."

The Reconstruction era was a period in American history following the American Civil War (1861–1865); it lasted from 1865 to 1877 and marked a significant chapter in the history of civil rights in the United States. Reconstruction, as directed by Congress, abolished slavery and ended the remnants of Confederate secession in the Southern states. It proclaimed the newly freed slaves (freedmen; black people) citizens with (ostensibly) the same civil rights as those of whites; these rights were nominally guaranteed by three new constitutional amendments: the 13th, 14th, and 15th, collectively known as the Reconstruction Amendments. Reconstruction also refers to the general attempt by Congress to transform the 11 former Confederate states and refers to the role of the Union states in that transformation.

In United States history, the Gilded Age was an era extending roughly from 1870 to 1900. It was a time of rapid economic growth, especially in the Northern and Western United States. As American wages grew much higher than those in Europe, especially for skilled workers, and industrialization demanded an ever-increasing unskilled labor force, the period saw an influx of millions of European immigrants.

The rapid expansion of industrialization led to real wage growth of 60% between 1860 and 1890, and spread across the ever-increasing labor force. Conversely, the Gilded Age was also an era of abject poverty and inequality, as millions of immigrants—many from impoverished regions—poured into the United States, and the high concentration of wealth became more visible and contentious.

Railroads were the major growth industry, with the factory system, mining, and finance increasing in importance. Immigration from Europe, and the Eastern United States, led to the rapid growth of the West, based on farming, ranching, and mining. Labor unions became increasingly important in the rapidly growing industrial cities. Two major nationwide depressions—the Panic of 1873 and the Panic of 1893—interrupted growth and caused social and political upheavals.

The "Gilded Age" term came into use in the 1920s and 1930s and was derived from writer Mark Twain and Charles Dudley Warner's 1873 novel The Gilded Age: A Tale of Today, which satirized an era of serious social problems masked by a thin gold gilding. The early half of the Gilded Age roughly coincided with the mid-Victorian era in Britain and the Belle Époque in France. Its beginning, in the years after the American Civil War, overlaps the Reconstruction Era (which ended in 1877). It was followed in the 1890s by the Progressive Era.

The Progressive Era (1896–1916) was a period of widespread social activism and political reform across the United States of America that spanned the 1890s to World War I. The main objectives of the Progressive movement were addressing problems caused by industrialization, urbanization, immigration, and political corruption. Social reformers were primarily middle-class citizens who targeted political machines and their bosses. By taking down these corrupt representatives in office, a further means of direct democracy would be established. They also sought regulation of monopolies through methods such as trustbusting and corporations through antitrust laws, which were seen as a way to promote equal competition for the advantage of legitimate competitors. They also advocated for new government roles and regulations, and new agencies to carry out those roles, such as the FDA.

The Spanish–American War (April 21 – August 13, 1898) was a period of armed conflict between Spain and the United States. Hostilities began in the aftermath of the internal explosion of USS Maine in Havana Harbor in Cuba, leading to United States intervention in the Cuban War of Independence. The war led to the United States emerging predominant in the Caribbean region, and resulted in U.S. acquisition of Spain's Pacific possessions. It led to United States involvement in the Philippine Revolution and later to the Philippine–American War.

The main issue was Cuban independence. Revolts had been occurring for some years in Cuba against Spanish colonial rule. The United States backed these revolts upon entering the Spanish–American War. There had been war scares before, as in the Virginius Affair in 1873. But in the late 1890s, American public opinion swayed in support of the rebellion because of reports of concentration camps set up to control the populace. Yellow journalism exaggerated the atrocities to further increase public fervor and to sell more newspapers and magazines.

The defeat and loss of the Spanish Empire's last remnants was a profound shock to Spain's national psyche and provoked a thorough philosophical and artistic reevaluation of Spanish society known as the Generation of '98. The United States meanwhile not only became a major power, but also gained several island possessions spanning the globe, which provoked rancorous debate over the wisdom of expansionism.

The United States declared war on the German Empire on April 6, 1917, nearly three years after World War I started. A ceasefire and Armistice was declared on November 11, 1918. Before entering the war, the U.S. had remained neutral, though it had been an important supplier to the United Kingdom, France, and the other powers of the Allies of World War I.

The U.S. made its major contributions in terms of supplies, raw material, and money, starting in 1917. American soldiers under General of the Armies John Pershing, Commander-in-Chief of the American Expeditionary Force (AEF), arrived at the rate of 10,000 men a day on the Western Front in the summer of 1918. During the war, the U.S. mobilized over 4 million military personnel and suffered the loss of 65,000 men. The war saw a dramatic expansion of the United States government in an effort to harness the war effort and a significant increase in the size of the U.S. Armed Forces.

After a relatively slow start in mobilizing the economy and labor force, by spring 1918, the nation was poised to play a role in the conflict. Under the leadership of President Woodrow Wilson, the war represented the climax of the Progressive Era as it sought to bring reform and democracy to the world. There was substantial public opposition to U.S. entry into the war.

The Roaring Twenties, sometimes stylized as Roarin' 20s, refers to the 1920s decade in music and fashion, as it happened in Western society and Western culture. It was a period of economic prosperity with a distinctive cultural edge in the United States and Europe, particularly in major cities such as Berlin, Buenos Aires, Chicago, London, Los Angeles, Mexico City, New York City, Paris, and Sydney. In France, the decade was known as the années folles ("crazy years"), emphasizing the era's social, artistic and cultural dynamism. Jazz blossomed, the flapper redefined the modern look for British and American women, and Art Deco peaked. In the wake of the military mobilization of World War I and the Spanish flu, President Warren G. Harding "brought back normalcy" to the United States.

The social and cultural features known as the Roaring Twenties began in leading metropolitan centres and spread widely in the aftermath of World War I. The spirit of the Roaring Twenties was marked by a general feeling of novelty associated with modernity and a break with tradition, through modern technology such as automobiles, moving pictures, and radio, bringing "modernity" to a large part of the population. Formal decorative frills were shed in favour of practicality in both daily life and architecture. At the same time, jazz and dancing rose in popularity, in opposition to the mood of World War I. As such, the period often is referred to as the Jazz Age.

The 20s decade saw the large-scale development and use of automobiles, telephones, films, radio, and electrical appliances in the lives of millions in the Western world. Aviation soon became a business. Nations saw rapid industrial and economic growth, accelerated consumer demand, and introduced significant new trends in lifestyle and culture. The media, funded by the new industry of mass-market advertising driving consumer demand, focused on celebrities, especially sports heroes and movie stars, as cities rooted for their home teams and filled the new palatial cinemas and gigantic sports stadiums. In many major democratic states, women won the right to vote.

In the United States, the Great Depression began with the Wall Street Crash of October 1929. The stock market crash marked the beginning of a decade of high unemployment, poverty, low profits, deflation, plunging farm incomes, and lost opportunities for economic growth as well as for personal advancement. Altogether, there was a general loss of confidence in the economic future.

The usual explanations include numerous factors, especially high consumer debt, ill-regulated markets that permitted overoptimistic loans by banks and investors, and the lack of high-growth new industries. These all interacted to create a downward economic spiral of reduced spending, falling confidence and lowered production. Industries that suffered the most included construction, shipping, mining, logging and agriculture (compounded by dust-bowl conditions in the heartland). Also hard hit was the manufacturing of durable goods like automobiles and appliances, whose purchase consumers could postpone. The economy hit bottom in the winter of 1932–1933; then came four years of growth until the recession of 1937–1938 brought back high levels of unemployment.

The Depression also resulted in an increase of emigration for the first time in American history. Some immigrants went back to their native countries, and some native U.S. citizens went to Canada, Australia and South Africa. There were mass migrations of people from badly hit areas in the Great Plains (the Okies) and the South to places such as California and the cities of the North (the Great Migration). Racial tensions also increased during this time. By the 1940s, immigration had returned to normal, and emigration declined.

The military history of the United States in World War II covers the victorious Allied war against the Axis Powers, starting with the 7 December 1941 attack on Pearl Harbor. During the first two years of World War II, the United States had maintained formal neutrality as made official in the Quarantine Speech delivered by US President Franklin D. Roosevelt in 1937, while supplying Britain, the Soviet Union, and China with war materiel through the Lend-Lease Act which was signed into law on 11 March 1941, as well as deploying the US military to replace the British forces stationed in Iceland. Following the "Greer incident" Roosevelt publicly confirmed the "shoot on sight" order on 11 September 1941, effectively declaring naval war on Germany and Italy in the Battle of the Atlantic. In the Pacific Theater, there was unofficial early US combat activity such as the Flying Tigers.

During the war some 16,112,566 Americans served in the United States Armed Forces, with 405,399 killed and 671,278 wounded. There were also 130,201 American prisoners of war, of whom 116,129 returned home after the war.

The war in Europe involved aid to Britain, her allies, and the Soviet Union, with the US supplying munitions until it could ready an invasion force. US forces were first tested to a limited degree in the North African Campaign and then employed more significantly with British Forces in Italy in 1943–45, where US forces, representing about a third of the Allied forces deployed, bogged down after Italy surrendered and the Germans took over. Finally the main invasion of France took place in June 1944, under General Dwight D. Eisenhower. Meanwhile, the US Army Air Forces and the British Royal Air Force engaged in the area bombardment of German cities and systematically targeted German transportation links and synthetic oil plants, as it knocked out what was left of the Luftwaffe post Battle of Britain in 1944. Being invaded from all sides, it became clear that Germany would lose the war. Berlin fell to the Soviets in May 1945, and with Adolf Hitler dead, the Germans surrendered.

Following World War II, the United States emerged as one of the two dominant superpowers, the Soviet Union being the other. The U.S. Senate on a bipartisan vote approved U.S. participation in the United Nations (UN), which marked a turn away from the traditional isolationism of the U.S. and toward increased international involvement.

The primary American goal of 1945–1948 was to rescue Europe from the devastation of World War II and to contain the expansion of Communism, represented by the Soviet Union. U.S. foreign policy during the Cold War was built around the support of Western Europe and Japan along with the policy of containment, stopping the spread of communism. The U.S. joined the wars in Korea and Vietnam and toppled left-wing governments in the third world to try to stop its spread.

In 1989, the fall of the Iron Curtain after the Pan-European Picnic and a peaceful wave of revolutions (with the exception of Romania and Afghanistan) overthrew almost all communist governments of the Eastern Bloc. The Communist Party of the Soviet Union itself lost control in the Soviet Union and was banned following an abortive coup attempt in August 1991. This in turn led to the formal dissolution of the USSR in December 1991, the declaration of independence of its constituent republics and the collapse of communist governments across much of Africa and Asia. The United States was left as the world's sole superpower.

The Civil Rights Movement was a time of great social and political change in the United States, during which African Americans and other minorities worked to end racial segregation and discrimination and achieve equal rights under the law. The movement began in the mid-1950s and continued into the late 1960s, and it was characterized by nonviolent protests, civil disobedience, and legal challenges to discriminatory laws and practices.

One of the key demands of the Civil Rights Movement was the desegregation of public spaces, such as schools, buses, and restaurants. In 1955, the Montgomery Bus Boycott was launched in Alabama after Rosa Parks, an African American woman, was arrested for refusing to give up her seat on a bus to a white person. The boycott, which lasted for over a year and involved the participation of tens of thousands of African Americans, resulted in the U.S. Supreme Court ruling that segregation on public buses was unconstitutional.

Another notable event in the Civil Rights Movement was the Little Rock Nine incident in 1957. Nine African American students attempted to enroll in Little Rock Central High School in Arkansas, but were prevented from doing so by a mob of white protesters and the National Guard, which had been ordered to the school by the Governor. President Dwight D. Eisenhower eventually sent federal troops to escort the students into the school, and they were able to attend classes there, but they faced continued harassment and violence.

The March on Washington for Jobs and Freedom, which took place in 1963, is one of the most well-known events of the Civil Rights Movement. The march, which was organized by a coalition of civil rights groups and was attended by more than 200,000 people, aimed to call attention to the ongoing struggle for civil rights and to demand that the government take action to end discrimination. During the march, Martin Luther King Jr., delivered his famous "I Have a Dream" speech, in which he called for an end to racism and for the realization of the American dream of freedom and equality for all people.

The Civil Rights Movement had great impact on American society, the movement helped to end legal segregation, it ensured that minorities have equal access to public facilities and the right to vote, and it helped to bring about a greater awareness of and opposition to racism and discrimination. It also had an impact on Civil Rights Movement around the world and many other countries got inspired by it.

The Cuban Missile Crisis was a 35-day confrontation between the United States and the Soviet Union, which escalated into an international crisis when American deployments of missiles in Italy and Turkey were matched by Soviet deployments of similar ballistic missiles in Cuba. Despite the short time frame, the Cuban Missile Crisis remains a defining moment in national security and nuclear war preparation. The confrontation is often considered the closest the Cold War came to escalating into a full-scale nuclear war.

After several days of tense negotiations, an agreement was reached: publicly, the Soviets would dismantle their offensive weapons in Cuba and return them to the Soviet Union, subject to United Nations verification, in exchange for a US public declaration and agreement to not invade Cuba again. Secretly, the United States agreed with the Soviets that it would dismantle all of the Jupiter MRBMs which had been deployed to Turkey against the Soviet Union. There has been debate on whether or not Italy was included in the agreement as well. While the Soviets dismantled their missiles, some Soviet bombers remained in Cuba, and the United States kept the naval quarantine in place until November 20, 1962.

When all offensive missiles and the Ilyushin Il-28 light bombers had been withdrawn from Cuba, the blockade was formally ended on November 20. The negotiations between the United States and the Soviet Union pointed out the necessity of a quick, clear, and direct communication line between the two superpowers. As a result, the Moscow–Washington hotline was established. A series of agreements later reduced US–Soviet tensions for several years, until both parties eventually resumed expanding their nuclear arsenals.

The Reagan Era or Age of Reagan is a periodization of recent American history used by historians and political observers to emphasize that the conservative "Reagan Revolution" led by President Ronald Reagan in domestic and foreign policy had a lasting impact. It overlaps with what political scientists call the Sixth Party System. Definitions of the Reagan Era universally include the 1980s, while more extensive definitions may also include the late 1970s, the 1990s, the 2000s, the 2010s, and even the 2020s. In his 2008 book, The Age of Reagan: A History, 1974–2008, historian and journalist Sean Wilentz argues that Reagan dominated this stretch of American history in the same way that Franklin D. Roosevelt and his New Deal legacy dominated the four decades that preceded it.

Upon taking office, the Reagan administration implemented an economic policy based on the theory of supply-side economics. Taxes were reduced through the passage of the Economic Recovery Tax Act of 1981, while the administration also cut domestic spending and increased military spending. Increasing deficits motivated the passage of tax increases during the George H. W. Bush and Clinton administrations, but taxes were cut again with the passage of the Economic Growth and Tax Relief Reconciliation Act of 2001. During Clinton's presidency, Republicans won passage of the Personal Responsibility and Work Opportunity Act, a bill which placed several new limits on those receiving federal assistance.

The September 11 attacks were a series of terrorist attacks carried out by the Islamic extremist group al-Qaeda on September 11, 2001. Four coordinated attacks were launched in the United States that day, with the goal of destroying symbolic and military targets. The attacks resulted in the deaths of 2,977 people, as well as significant destruction of property and infrastructure.

The first two attacks involved the hijacking and crashing of American Airlines Flight 11 and United Airlines Flight 175 into the North and South towers, respectively, of the World Trade Center complex in New York City. Both towers collapsed within hours, causing widespread destruction and fatalities.

The third attack targeted the Pentagon in Arlington, Virginia, just outside of Washington, D.C. American Airlines Flight 77 was hijacked and flown into the building, causing significant damage and loss of life.

The fourth and final attack of the day targeted either the White House or the U.S. Capitol Building, but the hijackers of United Airlines Flight 93 were ultimately thwarted by passengers, who attempted to overcome the hijackers and regain control of the plane. The plane crashed into a field near Shanksville, Pennsylvania, killing all on board.

The attacks were planned and executed by al-Qaeda, a terrorist organization that was led by Osama bin Laden. The group had previously carried out other attacks, including the 1998 U.S. embassy bombings in Kenya and Tanzania, but the September 11 attacks were by far the most devastating. The United States and its allies responded to the attacks with a series of military and diplomatic initiatives, including the U.S. invasion of Afghanistan to topple the Taliban regime, which had harbored al-Qaeda and other terrorist groups.

The 9/11 attacks has affected the entire world and it was considered as a turning point for USA and lead to many political and social changes. The attacks, and the broader War on Terror that followed, continue to shape international relations and domestic policies to this day.

The War on Terror, also known as the Global War on Terrorism or the War on Terrorism, is a military campaign launched by the United States and its allies in response to the September 11, 2001 terrorist attacks on the World Trade Center and the Pentagon. The stated goal of the War on Terror is to disrupt, dismantle, and defeat terrorist organizations and networks that pose a threat to the United States and its allies.

The War on Terror has been conducted primarily through military operations, but it also includes diplomatic, economic, and intelligence-gathering efforts. The United States and its allies have targeted a variety of terrorist organizations and networks, including al-Qaeda, the Taliban, and ISIS, as well as state sponsors of terrorism such as Iran and Syria.

The initial phase of the War on Terror began with the U.S. invasion of Afghanistan in October 2001, which was launched with the goal of toppling the Taliban regime, which had harbored al-Qaeda and other terrorist groups. The U.S. and its allies were able to quickly oust the Taliban and establish a new government, but the war in Afghanistan would become a prolonged conflict, with the Taliban regaining control in many areas.

In 2003, the United States launched a second military campaign as part of the War on Terror, this time in Iraq. The stated goal was to remove the regime of Saddam Hussein and to eliminate the threat of weapons of mass destruction (WMDs), which was later found to be non-existent. The overthrow of Saddam Hussein's government sparked a civil war in Iraq, which led to significant sectarian violence and the rise of jihadist groups, including ISIS.

The War on Terror has also been conducted through other means, such as drone strikes, special operations raids, and targeted killings of high-value targets. The War on Terror has also been used to justify various forms of surveillance and data collection by government agencies and the expansion of military and security operations around the world.

The War on Terror has met with mixed results, and it continues to be a major aspect of U.S. foreign policy and military operations to this day. Many terrorist organizations have been significantly degraded and have lost key leaders and operational capabilities, but others have emerged or re-emerged. Additionally, it was argue that the war on terror has caused significant human and civil right abuses, the displacement of millions of people, the spread of extremist ideologies, and has resulted in heavy financial costs.

The 2003 invasion of Iraq, also known as the Iraq War, was a military campaign launched by the United States, the United Kingdom, and a coalition of other countries, with the goal of removing the regime of Saddam Hussein and eliminating the threat of weapons of mass destruction (WMDs) in Iraq. The invasion began on March 20, 2003 and was met with little resistance from the Iraqi military, which quickly collapsed.

The justification for the war was primarily based on the claim that Iraq had WMDs and that they posed a threat to the United States and its allies. The Bush administration argued that these weapons could be used by Iraq or provided to terrorist groups for attacks on the U.S. and its allies. However, no significant stockpiles of WMDs were found after the fall of the regime and it was later determined that Iraq did not possess WMDs, which was a key factor that led to the decline of public support of the war.

The fall of Saddam Hussein's government was relatively quick and the U.S. military was able to capture Baghdad, Iraq's capital, in a matter of weeks. But the post-invasion phase quickly proved to be much more difficult, as an insurgency began to form, composed of remnants of the old regime, as well as religious and ethnic groups that opposed the presence of foreign troops in Iraq.

The insurgency was fueled by a number of factors, including the lack of a clear plan for post-war stabilization, inadequate resources to rebuild the country and provide essential services, and the failure to integrate the Iraqi military and other government institutions into the new government. The insurgency grew in strength, and the U.S. military found itself engaged in a prolonged and bloody conflict that lasted for years.

Additionally, the political situation in Iraq also proved to be complex and difficult to navigate, as various religious and ethnic groups struggled for power and influence in the new government. This led to widespread sectarian violence and ethnic cleansing, particularly between the majority Shia population and the minority Sunni population, which left hundreds of thousands of people dead and displaced millions.

The U.S. and its coalition partners eventually succeeded in stabilizing the country, but the war in Iraq has had significant long-term consequences. The cost of the war in terms of lives lost and dollars spent was enormous, as was the human cost in Iraq, with estimates of hundreds of thousands of people killed and millions displaced. The war was also one of the major factors that led to the rise of extremist groups in Iraq such as ISIS and continues to have a profound impact on U.S. foreign policy and global politics until this day.

The Great Recession in the United States was a severe economic downturn that began in December 2007 and lasted until June 2009. It was one of the worst economic crises in American history, and it had a profound impact on the country's economy, as well as on the lives of millions of people.

The Great Recession was triggered by the collapse of the U.S. housing market, which had been fueled by a boom in housing prices and a proliferation of risky mortgages. In the years leading up to the recession, many Americans had taken out adjustable-rate mortgages with low initial interest rates, but as housing prices began to decline and interest rates rose, many borrowers found themselves owing more on their mortgages than their homes were worth. As a result, defaults and foreclosures began to rise, and many banks and financial institutions were left holding large amounts of bad mortgages and other risky assets.

The crisis in the housing market soon spread to the broader economy. As the value of assets held by banks and other financial institutions fell, many firms became insolvent, and some even went bankrupt. Credit markets froze up as lenders became increasingly risk-averse, making it difficult for businesses and consumers to borrow the money they needed to invest, buy homes, or make other major purchases. At the same time, unemployment began to rise, as businesses laid off workers and cut back on spending.

In response to the crisis, the U.S government and the Federal Reserve implemented a range of measures to try to stabilize the economy. The government bailed out several large financial institutions and passed a stimulus package to try to stimulate economic growth. The Federal Reserve also cut interest rates to near zero, and implemented several unconventional monetary policies, such as quantitative easing, to try to stabilize the economy.

Despite these efforts, however, the Great Recession continued to take a heavy toll on the economy and on American society. The unemployment rate rose to a peak of 10% in October 2009, and many Americans lost their homes and their savings. The recession also had a significant impact on the federal budget and on the country's debt, as the government's stimulus spending and the cost of bank bailouts added trillions of dollars to the federal debt. Additionally, GDP dropped by 4.3% in 2008 and further by 2.8% in 2009.

It took several years for the economy to fully recover from the Great Recession. The unemployment rate eventually fell, and the economy began to grow again, but the recovery was slow and uneven. Some experts argue that the policies implemented by the government and the Fed prevented a deeper economic depression, but the impact of the recession was felt by many people for years to come, and it highlighted the fragility of the financial system and the need for better regulation and oversight.

The COVID-19 pandemic began in the United States in early 2020 and quickly spread throughout the country, leading to widespread illness, hospitalizations, and deaths. The disease is caused by a novel coronavirus, SARS-CoV-2, which was first identified in Wuhan, China in December 2019. The virus primarily spreads through respiratory droplets produced when an infected person coughs or sneezes, and it can cause a range of symptoms, from mild to severe.

The first confirmed cases of COVID-19 in the United States were reported in January 2020, and by March, the World Health Organization had declared the outbreak a global pandemic. The U.S. government initially downplayed the threat of the virus, but as the number of cases and deaths rapidly increased, officials began to take more serious measures to slow the spread of the disease. In March, a national emergency was declared and many state governors issued stay-at-home orders to try to curb the spread of the virus. Some of the country's largest cities also implemented lock-down policies to slow the spread of the virus. The restrictions, however, met with mixed response from the public. Some argued that it was necessary for public health, while others argued that it was an overreach of government power, and that it was causing severe economic damage.

The pandemic hit the United States particularly hard, in terms of both its human toll and its economic impact. As of January 2021, more than 22 million people in the United States have been infected with COVID-19, and more than 375,000 have died. The death rate has been higher among certain groups, including older adults, people with underlying health conditions, and communities of color. The pandemic has also had a significant economic impact, with millions of people losing their jobs and many businesses shutting down.

In response to the pandemic, the U.S government has undertaken a range of measures to try to slow the spread of the disease and support those affected by it. This includes the implementation of travel restrictions and quarantine requirements for people arriving from certain countries, as well as widespread testing and contact tracing efforts. Additionally, several vaccines have been developed and authorized for emergency use by the US FDA. The U.S government and private sectors also implemented financial relief programs, like the CARES act that were aimed at providing financial support to individuals and businesses affected by the pandemic.

Despite these efforts, however, the pandemic has continued to spread throughout the United States, with cases and deaths remaining high as of January 2021. Experts suggest that the country needs to continue its efforts to slow the spread of the virus, including through widespread testing, contact tracing, and vaccination, as well as promoting public health messaging. Also, the role of the government, public and private sectors, and the individual in reducing the spread of the virus is still an ongoing debate in the United States.