America’s first invasion of Canada in 1775 started off well. Colonel Benedict Arnold’s surprise attack through the Maine wilderness was a disaster, with troops having to eat their belts, but it fixed Governor Guy Carleton in Quebec, and allowed Brigadier General Richard Montgomery who moved north from Fort Ticonderoga to seize Montreal and besiege Quebec. On New Year’s Eve, a surprise assault in a blinding snowstorm was discovered by an alert sentry mere seconds before the Americans were over the wall. Montgomery was killed and the new commander Brigadier General John Thomas, with the headstrong Arnold (still an ardent patriot at this point in the war) settled in for a siege.
In May 1776, the first British and Hessian troops from Europe under General John Burgoyne arrived to put down the rebellion. With just 2000 men, Thomas couldn’t continue the siege and retreated toward Montreal. But the American governor there so alienated the population of the city that they banded together with a small outlying British garrison, and the Mississauga, Seneca, and Cayuga Indians to throw out the Americans. By this point Brigadier General John Sullivan arrived with reinforcements, saw the futility of trying to hold Montreal with a superior British approaching from Quebec, took command of everyone, and headed quickly back to Ft Ticonderoga.
They would have made it intact if they hadn’t been intentionally led astray by a Canadian guide on 8 June 1776. The treacherous canuck led the American army into a swamp while “looking” for the ford at Trois-Rivieres. By the time they extricated themselves Carleton’s vanguard caught them. In the chaos that followed, 50 Americans were killed and 230 captured. The British had ten casualties.
Sullivan still managed to save the bulk of the men, which prevented Burgoyne from invading the nascent United States in 1776, but America’s first invasion of Canada had failed.