Even before the United States became a country, its leaders had their eyes on the colonies to the north. Army commander George Washington sent troops led by Benedict Arnold to capture Quebec during the Revolutionary War in an unsuccessful bid to get Canadians to join the rebel cause.

During the War of 1812, there were multiple U.S. attempts to capture parts of Canada. And by the mid-19th century, Secretary of State William Seward made clear his belief that the United States was destined to expand northward. Most in the Great White North consistently rejected the idea of becoming part of the United States. Some historians argue this sentiment contributed to the 1867 decision of three British North American colonies—Nova Scotia, New Brunswick and the Province of Canada—to unite and form a self-governing Dominion of Canada.

“How Canada was created, and when Canada was created, and why Canada was created, was to stand against the annexation plans of the United States,” says John Boyko, Canadian author of Blood and Daring: How Canada Fought the American Civil War and Forged a Nation.

In 1777, soon after declaring American independence, the Founding Fathers included in the young nation’s Articles of Confederation a direct invitation to colonists to the North to join the newly formed country, so long as it ended its relationship with Britain. The invitation stood open until the U.S. Constitution was ratified in June 1788 and a new government took office in March 1789.

By the early 1800s, the U.S. and Britain faced rising tensions amid trade disputes and the British impressment of American sailors. This led to the War of 1812, during which the United States attempted to capture different parts of Canada but was repelled by Canadian, British and Indigenous forces. U.S. forces raided and burned government buildings in York (now Toronto), and the British retaliated by torching public buildings in Washington, D.C.

In the 1840s, as Britain began moving toward an economic policy of free trade, it repealed a series of protective tariffs in Canada known as the Corn Laws. This left Canada in a state of economic uncertainty and fueled resentment toward the British, leading a small but prominent group of about 325 Montreal merchants to publish a manifesto calling for Canada’s annexation to the United States in 1849.

The effort was short-lived and largely diffused when Britain negotiated a trade deal between Canada and the United States in 1854. Canada’s economy recovered.

Seward, the New York senator who became Secretary of State after Abraham Lincoln's election in 1860, advocated for the new treaty, believing it could help lay the groundwork for an eventual annexation of Canada, according to Boyko.

While campaigning for Lincoln’s presidency earlier that year, Seward directly addressed Canadians in a speech in St. Paul, Minnesota, saying, “It is very well you are building excellent states to be hereafter admitted into the American Union.”

Most talk of annexation was paused during the American Civil War, which broke out in 1861. After the Union’s victory in 1865, the U.S. Congress expressed anger toward Britain for its indirect support of the Confederacy during wartime. 

Meanwhile, a group of Irish-Americans called the Fenians began launching small, unsuccessful raids across Canada in 1866, driven by their fight for Irish independence from Britain. Their fifth and final incursion ended in retreat in 1871. 

Whether or not grounded in reality, the possibility of an official U.S. invasion of British North America worried Canadians. "Either we must obtain a British North American Confederation or be absorbed in an American Confederation,” parliamentarian George-Étienne Cartier said in 1865.

These concerns escalated when, in 1866, Congress canceled its free trade agreement with Canada, weakening economic ties. That same year, Rep. Nathaniel P. Banks of Massachusetts introduced a bill calling for the annexation of British North America. It never came to a vote.

Seward didn’t push as openly or passionately for an annexation of Canada as he did for Alaska, but he argued that America’s expansion across North America was inevitable, says Lee Farrow, author of Seward's Folly: A New Look at the Alaska Purchase and professor of history at Auburn University at Montgomery.

“There was a spirit of expansionism that many people embraced, and [Seward] had big dreams for the United States,” Farrow says.

The U.S. signed the Alaska Purchase Treaty on March 30, 1867 to solidify its purchase of the territory from Russia. But one day earlier, as Canadian fears mounted, the Queen of England gave assent to the British North America Act. It established four provinces—Nova Scotia, New Brunswick, Ontario and Quebec—that made up the Dominion of Canada (as part of the British empire).

“There was this belief that anyone, given the opportunity, would become an American, and there was a failure to understand that most Canadians didn’t feel that way,” says Stephen Azzi, author of Reconcilable Differences: A History of Canada–U.S. Relations and professor at Carleton University in Ottawa, Canada. 

The colony of British Columbia, however, didn’t immediately join the dominion. Several American newspapers, including the St. Louis Times and New York World, endorsed the idea of absorbing British Columbia. 

Seward tried asking for parts of the colony as payment for damage claims that the U.S. brought against Great Britain after the Civil War. Those efforts failed.

Illinois Representative Green B. Raum said in 1868 he thought British Columbia would “drop into our hands like a ripe pear.” In a report published that year, Seward expressed hopes of acquiring Greenland and Iceland—and that doing so might entice Canada to join.

He also expressed interest in buying Rupert’s Land, a vast North American territory spanning 1.5 million square miles. But in 1870, the Hudson’s Bay Company, a British corporation, transferred sold the land to Canada.

British Columbia then joined Canada in July 1871. 

After two decades of an economic depression in Canada, the idea of annexing Canada resurfaced in 1890 when lawmakers passed the McKinley Tariff, which significantly raised tariffs on imported goods to protect American industries.

U.S. lawmakers hoped Canada would join America to avoid these tariffs. But the plan backfired, according to Time. John A. Macdonald, the Conservative Prime Minister of Canada, retaliated by implementing higher tariffs on American goods and increasing trade with Britain. The topic became a major talking point of his successful reelection campaign in 1891.

In 1911, Canadian Prime Minister Wilfrid Laurier, proposed a free trade agreement with the United States. The agreement was accepted by the U.S. Congress but rejected by Canadians, with Laurier facing a resounding defeat in his own reelection bid.

That same year, New York Rep. William Bennet introduced a House Resolution asking President William Howard Taft to start talks with Great Britain over annexing Canada.

Canada gained its full independence in 1982 and went on to become a close trading partner and military ally with the United States.