Washington: Donald Trump signed an executive order to rename Lake Ontario – which sits between the US and Canada – to “Lake America” amid an ongoing trade war between the two North American neighbours and allies.

The US president’s order instructs his interior secretary, Doug Burgum, to change the lake’s official name in the US through the Geographic Names Information System, and remove all references to Lake Ontario on department and agency maps, contracts and other documents.

Trump made the announcement in the Oval Office with an enlarged map of Lake Ontario with the words “Lake America” stamped over it in red, as well as a cardboard sign that said: “Making the Great Lakes Even Greater”.

He floated the change several days ago after a trade war with Canada escalated on the weekend. Prime Minister Mark Carney withdrew from trade negotiations saying the Americans had made a series of last-minute changes and demands that were unacceptable to Canada.

Canada will now impose 50 per cent tariffs on about $US20 billion ($28 billion) worth of additional American goods, matching the 50 per cent US tariffs that began on Saturday.

“Canada has been ripping us off for a long time on trade, very sadly,” Trump said on Thursday (Washington time). “They don’t pay us to defend Canada, but we defend Canada. They don’t pay for anything.

“But they want to be treated like they’re a [US] state. We just can’t do that any more.” He said his problem was with Canadian government officials, who were “nasty people” and “entitled”, not the people of Canada.

White House staff secretary Ben Moss added: “This is a lake that has most of its volume in the United States. The deepest parts of the lakes are in United States territory. So, this will reflect that this is an American lake.”

The move is reminiscent of Trump’s decision early in his second term to name the Gulf of Mexico the “Gulf of America”, a change that has been partly adopted by other organisations. For example, Google Maps shows the body of water as the Gulf of America.

Trump added that he had been thinking about changing the name of Lake Ontario for a long time. “We have a gulf, and we have a lake. Now all we need is an ocean,” he said. “So, maybe we’ll have to change the name of the Atlantic and/or the Pacific [oceans]. Maybe we’ll change them both.”

The International Hydrographic Organisation – of which both the United States and Canada are members – works to ensure that the world’s seas, oceans and navigable waters are surveyed and charted uniformly, and also names some of them. But there is no single international body that determines names of international bodies of water.

The US and Canada share borders along multiple Great Lakes, including Lake Ontario, which sits between Canada’s Ontario province and upstate New York State. Ontario is also the single largest export destination for more than a dozen US states.

Responding to Trump’s announcement, Carney noted the name Lake Ontario came from the word “Ontari’io”, belonging to the native Wendat people of the Great Lakes, which meant “the lake is beautiful, the lake is big”.

The name predates European settlement and, as Carney noted, the Declaration of Independence of the United States of America.

“We know that America is changing,” he wrote on X. “Their trading relationships, their foreign policies, their national monuments, their hydronyms. Canadians also know that naming reality means calling it Lake Ontario – then, now and always.”

Hours after Trump hosted his Oval Office news conference, he posted a note on social media from Ned Mamula, director of the US Geological Survey, affirming that the change had been made.

With AP

Get a note directly from our foreign correspondents on what’s making headlines around the world. Sign up for our weekly What in the World newsletter.