For most of the war, Americans entertained the illusion that Canada was ripe for the picking, that freedom-craving Canadians would rally to the American call and join them in ousting their common British foe. For most of the war, Americans also realized that Canada provided Britain with a valuable base, an easily-supplied staging ground from which they could launch attacks into New England and New York.
Therefore ideology and pragmatism combined to encourage Americans to take their war for independence to Canada which they did for first time in the late fall of 1775. Informed that the British intended to send an army south from Canada under Governor Guy Carleton to capture New York, the Continental Congress dispatched General Philip Schuyler and a force of about 1000 militia in August 1775 toward Montreal by way of Lake Champlain. At the same time, General Washington ordered Benedict Arnold to recruit an army in Massachusetts and march toward Quebec.
Schuyler, and Richard Montgomery who succeeded Schuyler when he fell ill, enjoyed rapid success all the way to Montreal, which was captured on 13 November. Arnold, however, badly underestimated the distance he had to travel and the severity of the terrain he had to cross; therefore, his force was badly depleted by the time it reached Quebec in November. Desertion and disease further reduced his 1000-man army to about 675. Montgomery tried to help; he led 300 men from Montreal to Quebec in December, but they would not prove enough against the fortified walls of the Canadian city and the 1800 British troops inside.
December was hardly the best time to attack. Arnold might have been wise to lay siege to the city and attack when the supplies inside ran short. But the enlistment of many of his men ran out at the end of the year, and the spring thaw would probably bring British re-enforcements down the St. Lawrence. Arnold believed he could not wait, and so on 31 December, in the middle of a blizzard, he ordered an attack.
American forces slogged through freezing temperatures and driving winds to reach the city walls. The British waited for them inside. Almost as soon as the fighting began, Montgomery was killed and Arnold took a bullet in the leg. Within just hours, the American forces were defeated. Fewer than 100 Americans were killed or injured, but 400 were captured. Refusing to accept defeat, Arnold set camp below the city and waited for re-enforcements. Over the next several months several hundred did arrive. But small pox took an almost equal number leaving his besieging army still undermanned by the spring. In March, Arnold was ordered to Montreal; David Wooster, and then John Thomas took command of the struggling American army outside Quebec. But when British re-enforcements did sail up the St. Lawrence with the spring thaw, Thomas ordered his army to withdraw in May 1776.
The failure of the Canadian campaign tempered hopes raised by the Patriots’ impressive showing at Bunker Hill. One promising commander, Richard Montgomery, was killed in battle; a second, John Thomas, died of small pox. Some dreamed of a second campaign in Canada. These believed that Canadians might still rally to the promise of freedom offered by the Americans. But in the meantime, the province of Quebec remained in British hands, and provided a valuable staging ground for the campaigns of 1777 and 1778.