The U.S.-Canada border, as seen on this satellite tv for pc map, largely runs alongside the forty ninth parallel — and wasn’t chosen at random.
Planet Observer/Common Photos Group by way of Getty Photos
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Planet Observer/Common Photos Group by way of Getty Photos
When President Trump hosted Canadian Prime Minister Mark Carney within the Oval Workplace, dialog turned not solely to the connection between the 2 international locations, however to the border itself.
Echoing a phrase he has utilized in latest months, Trump described the U.S.-Canada border as an “artificially drawn line” — and advised it must be erased.
“Somebody drew that line many years ago … like with a ruler, just a straight line right across the top of the country,” Trump mentioned at Tuesday’s assembly. “When you look at that beautiful formation, when it’s together — I’m a very artistic person — but when I looked at that beaut, I said, ‘That’s the way it was meant to be.’ “
Trump: “To be honest with you, Canada only works as a state. We don’t need anything they have. As a state it would be one of the great states. This would be the most incredible country visually. If you look at a map, they drew an artificial line right through it.” pic.twitter.com/oxzF3jzLOC
— Aaron Rupar (@atrupar) March 13, 2025
Trump has set his sights on Canada since taking workplace, speaking repeatedly of constructing it the 51st U.S. state. He additionally hit the nation — one of many U.S.’ prime buying and selling companions — with a 25% tariff on most items, additional antagonizing Canadians. That backlash is credited with propelling Carney — who campaigned on standing as much as the president — to an surprising election victory final month.
Carney informed Trump that Canada will not be on the market, and “won’t be for sale, ever.”
However by describing the boundary line as synthetic, Trump appears to counsel in any other case, says Jon Parmenter, a historical past professor at Cornell College. He says the president’s characterization of the border downplays “the fact that it has a complex, deep history and that it is an important part of everyday life on the North American continent.”
“It’s a real thing,” says Parmenter, who teaches a category on the U.S.-Canada border. “And it concerns me, as a historian, to hear people dismissing it as something that’s artificial … or in a sense, illegitimate.”
Carney later informed reporters he was “glad you could not tell what was going through my mind” throughout that dialog.
The U.S.-Canadian border is the longest worldwide border on the planet, stretching 5,525 miles throughout North America. A lot of the border appears like a straight line as a result of it basically is: The road largely follows the forty ninth parallel (of latitude north of the equator), whereas a smaller swath traces the forty fifth parallel.
The border is technically man-made: It was drawn on a map by the governments of America and Britain, which managed Canada till 1867. In that method, Parmenter says, it — like all borders — is a assemble.
“These are things that people decide makes sense at a particular moment in time,” he says.
However simply because it is not a naturally occurring border — like a mountain vary or an ocean — does not imply it is not legit.
“The border is artificial in the sense that it’s not something that … people living in proximity to it had any kind of role in making,” he explains. “But it’s not artificial in the sense that it’s not real, and that it doesn’t matter, and there aren’t real-world consequences for traversing it in a manner that is deemed to be illicit.”
How the border got here to be

This 1861 illustration exhibits the boundary line between america and Canada.
The Print Collector/Heritage Photos by way of Getty Photos
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The Print Collector/Heritage Photos by way of Getty Photos
The U.S.-Canada boundary was formed by a sequence of treaties that befell between 1783 and 1925.
The primary was the Treaty of Paris, which ended the American Revolution, acknowledged American independence and set the Mississippi River because the western border of the brand new U.S. — which continued to increase all through the nineteenth century.
Years later, the Conference of 1818 formally established the border between the U.S. and British North America — later Canada — on the forty ninth parallel, from Lake of the Woods, Minn., to the Rocky Mountains. The Oregon Treaty of 1846 prolonged the border to the Pacific Ocean.
“People sort of sat down and were going back and forth, and lines of latitude became the easiest way to resolve a dispute over who got what,” Parmenter says.
Stephen Hornsby, a professor of geography and Canadian research on the College of Maine, says the selection of the forty ninth parallel particularly was no coincidence.
The British needed to protect the northern a part of the continent for the fur commerce, whereas the U.S. needed as a lot of the Mississippi basin as doable for agricultural settlement, Hornsby explains. They determined to separate the wind up based mostly on the river programs, which on the time had been the principle method of touring across the continent.
The forty ninth parallel, Hornsby says, made for an “extraordinarily convenient dividing line.” Nearly all the rivers to the north move out by means of the St. Lawrence River system or the Hudson Bay, whereas rivers to the south move into the Mississippi River and Gulf of Mexico.
“Although it seems like a straight line across the land, when you start to look at the river systems and the larger watersheds, it’s basically a dividing line between the watersheds north and south of that line,” Hornsby says, including that “it all makes perfect sense” on a map of North American river programs.
It did not essentially make good sense in actual life, nevertheless. Parmenter says traces of latitude did not bear in mind geographical formations or the normal territories of Indigenous individuals already residing there.
“There are Indigenous nations whose territories actually spanned what became the U.S.-Canada border, who come to find out when the survey happens, ‘Oh, guess what, this is going right through the middle,’ ” he says. The Mohawk neighborhood of Akwesasne, in northern New York, is one instance.
How the border is demarcated
Over the following many years, as individuals moved westward and north, the U.S., the U.Okay., Canada and Russia negotiated some two dozen agreements, conventions and treaties to redefine the border, based on the Worldwide Boundary Fee (IBC) — which itself was created by treaty in 1908 to survey and map the border.
“It’s a very piecemeal process,” Parmenter says. “It sort of essentially is progressively drawn in a westward direction, but over time. So the Great Lakes area gets resolved, the prairie area gets resolved. The Pacific Coast and Alaska get resolved. And what you have left over is the longest international boundary on the face of the Earth, one that’s a very diverse border.”
Parmenter says there are numerous ranges of “intensity and frequency of crossing as you go east to west.” Some stretches of the border are actively monitored, together with with helicopters and drones. However others, particularly in distant areas, are marked solely by monuments, like an obelisk or strategically positioned rocks.
“In many places, it is a very permeable border,” he says.
As a part of its mission to have a tendency the border, the IBC says it inspects and maintains over 8,000 monuments and reference factors and 1,000 survey management stations. It additionally retains a 20-foot huge treeless zone — referred to as the vista — alongside the land boundary line.
“To make the boundary visible and unmistakable, we clear and maintain a swath called a vista that extends 10 feet on either side of the line through dense forests, over mountain ranges, across wetlands and highlands and some of the most rugged terrain North America has to offer,” its web site reads.
The vista, additionally referred to as the Slash, largely spans distant areas however is seen from sure land crossings, in addition to Google Earth.

A U.S. border patrol agent rides an ATV alongside “the Slash”— the boundary marker minimize into the forest — marking the road between Canadian territory on the fitting and the U.S., close to Beecher Falls, Vt.
Joe Raedle/Getty Photos
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Joe Raedle/Getty Photos
The place issues stand
Parmenter, a twin U.S.-Canadian citizen, says, “People are on alert in Canada about this.”
He says there may be way more consciousness of the border in Canada as a result of such a excessive proportion of the inhabitants — by some estimates, as a lot as 90% — lives inside 150 miles of it.
Proportionally, far fewer People cope with the northern border every day — and till not too long ago have been way more centered on its southern border with Mexico, he says.
Whereas the U.S.-Canada border has been steady for a century, it is also true that it was renegotiated a number of occasions in its early years. However Parmenter does not suppose which means a change is probably going now, particularly given Trump’s tariffs and the general state of affairs.
“It’s always the case that in any relationship, things can get better, and I think that both sides would agree that there are some ways in which the management of this particular border could be improved,” he says. “But the way to go about it is through sober and thoughtful negotiations, not ultimatums, not extreme rhetoric, not talk of annexation, because all that’s done is to alienate Canadian people.”