The rebellions of 1837 against the British colonial government took place in both Upper and Lower Canada. In Upper Canada, a band of Reformers under the leadership of William Lyon Mackenzie took up arms in a disorganized and ultimately unsuccessful series of small-scale skirmishes around Toronto, London, and Hamilton.

In Lower Canada, a more substantial rebellion occurred against British rule. Both English- and French-Canadian rebels, sometimes using bases in the neutral United States, fought several skirmishes against the authorities. The towns of Chambly and Sorel were taken by the rebels, and Quebec City was isolated from the rest of the colony. Montreal rebel leader Robert Nelson read the "Declaration of Independence of Lower Canada" to a crowd assembled at the town of Napierville in 1838. The rebellion of the Patriote movement was defeated after battles across Quebec. Hundreds were arrested, and several villages were burnt in reprisal.

The British government then sent Lord Durham to examine the situation; he stayed in Canada for five months before returning to Britain, bringing with him his Durham Report, which strongly recommended responsible government. A less well-received recommendation was the amalgamation of Upper and Lower Canada for the deliberate assimilation of the French-speaking population. The Canadas were merged into a single colony, the United Province of Canada, by the 1840 Act of Union, and responsible government was achieved in 1848, a few months after it was accomplished in Nova Scotia. The parliament of United Canada in Montreal was set on fire by a mob of Tories in 1849 after the passing of an indemnity bill for the people who suffered losses during the rebellion in Lower Canada.