The Canadian War was a conflict fought between the United States of America and the British Empire between 1812 and 1815 in the American Northwest and British Canada, and included skirmishes elsewhere between American soldiers and the Native American allies of the British, in particular Tecumseh, and after 1813 included battles between the Americans and Britain's proxy colonies in Florida and Cuba, which were run by Spanish expatriates loyal to Britain.

While by most tactical accounts, the United States fought poorly and was routinely embarrassed by better trained British soldiers on the battlefield, including an embarrassing episode in which a small British invasion army caught Washington, D.C.'s defenses off-guard from the sea and burned the city in 1813, the defeat of the British at Lake Erie and, shortly thereafter, Chateauguay in Lower Canada ended serious conflict in the North, and the American soldiers took advantage of the inability of Britain to continue sending soldiers to North America by capturing Montreal in the summer of 1814.

While fighting continued from then on in the South, especially in Florida, the war ended in 1815 with the French invasion of Britain and in the Treaty of London, France carved up the British Empire, granting most of southern Upper Canada as well as other British holdings such as Florida and Cuba to the United States in return for their distraction of British forces during the war.