Beginning in August 1775, American privateers raided towns in Nova Scotia, including Saint John, Charlottetown, and Yarmouth. In 1776, John Paul Jones and Jonathan Eddy attacked Canso and Fort Cumberland respectively. British officials in Quebec began negotiating with the Iroquois for their support, while US envoys urged them to remain neutral. Aware of Native American leanings toward the British and fearing an Anglo-Indian attack from Canada, Congress authorized a second invasion in April 1775.

The Invasion of Quebec was the first major military initiative by the newly formed Continental Army during the American Revolutionary War. The objective of the campaign was to seize the Province of Quebec (part of modern-day Canada) from Great Britain, and persuade French-speaking Canadiens to join the revolution on the side of the Thirteen Colonies. One expedition left Fort Ticonderoga under Richard Montgomery, besieged and captured Fort St. Johns, and very nearly captured British General Guy Carleton when taking Montreal. The other expedition, under Benedict Arnold, left Cambridge, Massachusetts and traveled with great difficulty through the wilderness of Maine to Quebec City.

Montgomery's expedition set out from Fort Ticonderoga in late August, and in mid-September began besieging Fort St. Johns, the main defensive point south of Montreal. After the fort was captured in November, Carleton abandoned Montreal, fleeing to Quebec City, and Montgomery took control of Montreal before heading for Quebec with an army much reduced in size by expiring enlistments. There he joined Arnold, who had left Cambridge in early September on an arduous trek through the wilderness that left his surviving troops starving and lacking in many supplies and equipment.