The Siege of Fort Mackinac marked one of the initial confrontations of the War of 1812, where a combined British and Native American force captured Mackinac Island shortly after the war's outbreak. Mackinac Island, situated between Lake Michigan and Lake Huron, was a vital U.S. fur trading post with influence over Native tribes in the region. British and Canadian traders had long resented its cession to the United States following the American Revolutionary War. The fur trade played a crucial role in the local economy, drawing Native Americans from modern-day Michigan, Minnesota, and Wisconsin to trade furs for goods. As war loomed, many Native American tribes opposed American westward expansion and were eager to join forces with the British.

Major General Isaac Brock, the British commander in Upper Canada, acted swiftly upon learning of the outbreak of war and ordered the capture of Fort Mackinac. Captain Charles Roberts, stationed at St. Joseph Island, assembled a diverse force, including British soldiers, Canadian fur traders, Native Americans, and recruited tribes from Wisconsin. Their surprise attack on Mackinac Island on July 17, 1812, caught the American garrison off guard. A single cannon shot and a flag of truce led to the fort's surrender without a fight. The island's inhabitants swore allegiance to the United Kingdom, and British control of Mackinac Island and northern Michigan remained largely unchallenged until 1814.

The capture of Fort Mackinac had broader implications for the war effort. It led to the abandonment of Brigadier General William Hull's invasion of Canadian territory, as the mere threat of Native American reinforcements prompted him to retreat to Detroit. The loss of Mackinac also swayed other Native communities to support the British cause, influencing the U.S. surrender at the Siege of Detroit. While British control persisted in the region for some time, challenges arose in 1814, leading to confrontations such as the Battle of Mackinac Island and engagements on Lake Huron.