The invasion of Canada in 1775-76 was the first major military initiative by the Americans during the Revolutionary War. After some early success by revolutionary forces, British and Canadian forces totally defeated the invasion.
In June 1775, the Continental Congress, influenced by reports that the British commander in Canada was recruiting a force in preparation for an invasion of New York and by hopes that Canada, largely inhabited by French, might become a fourteenth colony in support of the Revolutionary War, authorized seizure of any vital points in Canada needed to guarantee the security of the colonies. Consequently, a 2-pronged invasion of Canada was launched in the early fall of 1775.
Congress authorized Maj. Gen. Philip Schuyler, commander of the Northern Department, to mount an invasion to drive British forces from Canada. He sent Brig. Gen. Richard Montgomery north with an invasion force. Gen. George Washington also sent Col. Benedict Arnold towards Quebec with a supporting force.
Arnold, starting from Cambridge, Massachusetts, with about 1,100 men, went by water and land through the Maine wilderness on an epic march up the Kennebec and down the Chaudiere Rivers, arriving before Quebec on November 8 with only 650 men. There, he had to await the arrival of Brig. Gen. Richard Montgomery, who had taken over command of a force of about 2,000 men organized at Fort Ticonderoga by Maj. Gen. Philip Schuyler for an advance up the historic Lake Champlain-St. Lawrence River route. Beginning on September 17, Montgomery laid siege to the British fort at St. Johns, which fell on November 2, opening up the way to American occupation of Montreal on November 13. Finally, Montgomery joined Arnold near Quebec on December 3, but with only 300 men, the rest of his force staying behind to garrison St. Johns and Montreal.
With enlistments of most of the volunteer troops expiring at the end of the year, the two commanders decided to undertake a desperate night attack on Quebec on December 30-31, 1775. A composite British garrison repelled the assault, killing or wounding about 100 Americans and taking over 400 prisoners. Montgomery was among those killed.
In spite of these severe losses, the Americans continued to besiege the city until the spring of 1776. British forces in Canada were strengthened by troops under Gen. John Burgoyne and Hessian mercenaries. With the additional troops, the reinforced British garrison, led by Gen. Sir Guy Carleton, drove the Americans, who had already begun a retreat, back to the head of Lake Champlain.