Movements for the annexation of Canada to the United States

Since the independence of the United States, various movements within Canada and the United States have campaigned in favor of U.S. annexation of parts of or all of Canada.

In the early years of the United States, many American political figures were in favour of invading and annexing Canada and even pre-approved the admission of the Province of Quebec to the U.S. in the Articles of Confederation in 1777. During the American Revolutionary War, the Americans invaded the St. Lawrence River Valley, but were repelled. Americans also fought the British and allied Indigenous peoples in the Ohio Country — what was then the southwest of Quebec; at the end of the war, the land south of the Great Lakes was ceded to the newly independent United States and became the Northwest Territory. In the War of 1812, the Americans again invaded British North America in reprisal for the British impressment of American sailors on the high seas and support for Indigenous peoples resisting American westward expansion, but were repulsed again.

During and after the American Civil War, several American politicians called for the annexation of the Province of Canada because of Britain's material support for the Confederacy, which one historian asserts lengthened the war by two years, mostly inflicted by Confederate blockade runners (which were mostly British-built) delivering arms supplies primarily from Britain.^[1][2] Confederate agents operating in Canada received support from a large portion of Canadians throughout the war, allowing the British colony to be used as a base to attack the U.S., such as in the St. Albans Raid.^[3] In the 1872 Alabama Claims, the U.S. was compensated $15.5 million in war reparations by the British for damages caused only by British-built Confederate commerce raiders, as part of the 1871 Treaty of Washington. Historian Joseph Levitt notes:

Since the Treaty of Washington in 1871, when it first de facto recognized the new Dominion of Canada, the United States has never suggested or promoted an annexationist movement in Canada. No serious force has appeared on the American political scene that aimed to persuade or coerce Canadians into joining the United States. And no serious initiative for any move in this direction has come from the Canadian side either.^[4]

Surveys have suggested that a minority of Canadians would potentially support annexation, ranging from as many as 20 percent in a survey by Léger Marketing in 2001^[5] to as few as seven percent in another survey by the same company in 2004.^[6]

Since his election victory in 2024, U.S. President Donald Trump has renewed calls for Canada to be annexed as the 51st state of the United States.^[7] Canada responded strongly against these calls, with Prime Minister Justin Trudeau saying on Twitter that "[t]here isn't a snowball's chance in hell that Canada would become a part of the United States".^[8][9]