The 1775 American invasion of Quebec failed due to winter, starvation, and political miscalculation.
In late 1775, American forces attempted to seize Quebec City, hoping French Canadians would join their revolution. Instead, they faced a brutal wilderness trek, internal divisions, and a fortified British garrison. The resulting defeat on New Year's Eve marked the first major American failure of the Revolutionary War.
The invasion was a two-pronged effort authorized by the Second Continental Congress. Major General Richard Montgomery led forces from the south, capturing Montreal in November 1775, while Benedict Arnold commanded a separate expedition through the Maine wilderness. Arnold’s march was catastrophic; intended to take 20 days, it lasted far longer, forcing starving soldiers to eat their own leather shoes and belts. Of the 1,100 men who began the journey, only about 600 reached the St. Lawrence River in early November.
American leaders fundamentally misunderstood the local population. They assumed French Canadian habitants would welcome them as liberators from feudalism. In reality, the habitants—tenant farmers who valued neutrality—were largely satisfied with the British administration, which had recently restored their civil rights and protected the Catholic Church via the Quebec Act of 1774. Meanwhile, British Governor Guy Carleton mobilized a defense that included regular troops, militia, and Scottish Highland immigrants, while effectively ignoring the advice of local English-speaking 'Old Subject' businessmen who had lobbied for an American invasion to secure their own political dominance.
On December 31, 1775, Montgomery launched a desperate assault on Quebec City during a blinding snowstorm. The plan to converge on the lower city collapsed when Montgomery was killed by cannon fire. Arnold was wounded, and Daniel Morgan, who took command, was eventually trapped and forced to surrender. More than 400 Americans were taken prisoner. The defeat left the remaining American forces in an ineffectual blockade until spring, when British reinforcements arrived, effectively ending the campaign to bring Canada into the American fold.
Source: Battle of Quebec (1775)