General Philip Schuyler, commander of the American Army from New York, had instructions permitting him to capture any other part of the country provided that it would not be disagreeable to the Canadians!
Many of the Americans allegedly believed that Canadians would welcome an invasion to relieve them from “British tyranny.” Indeed, some Canadian businessmen did support the American cause. They even managed to send a Canadian battalion to help General Montgomery!
Before trying to capture Montreal, the Americans had to defeat a British force stationed at Saint-Jean-Sur-Richelieu. Its commander, Charles Preston, had 600 troops. Although Brigadier General Richard Montgomery surrounded the fort with a larger force, and urged Preston to surrender, the British commander held out through September and October.
Brigadier General Richard Montgomery had to take complete command of General Philip Schuyler because he became too ill to continue.
Meanwhile, Governor Guy Carleton had arrived in Montreal from Quebec and was trying to raise a force so he could rescue Preston at St. Jean. He had 200 regulars, and some of the seigniors had persuaded about 1,200 habitants to join up. These habitants didn’t really like the war, or being taken from their farms when they should be doing their plowing. So some of them deserted every night.
Carleton tried to take his force across the St. Lawrence on the night of October 30, but he was unable to land because of American gunfire. Major Preston had to surrender on November 3, and the way was now open for the Americans to march to Montreal.
Carleton’s only hope was to try to save Quebec. To get there, he made a spectacular trip down the river in disguise, right under the noses of the American patrols. He arrived just as General Benedict Arnold was beginning his attack on the city, and he maintained Quebec’s defence until the following May, when the siege was lifted by the arrival of units of the Royal Navy.
For more, visit Wikipedia’s page about the siege at Fort St. Jean.