US President Donald Trump has signed an executive order seeking to rename Lake Ontario to Lake America.

The move comes after trade talks between the US and Canada collapsed late last week, and the US imposed new 50% tariffs on $20bn (C$28bn) worth of Canadian goods. Canada will implement “dollar for dollar” counter tariffs next month.

Trump has repeatedly posted threats about renaming the lake, one of the five Great Lakes that straddle both countries, on social media amid the trade dispute.

He said on Thursday the move was “official, effective immediately” and that his administration has “filed all the necessary papers, documents” to make the change.

Canadian Prime Minister Mark Carney noted the name Lake Ontario can be traced back more than 400 years, adding in a social media post on Thursday that preceded the formation of the Canadian Confederation and the US Declaration of Independence.

“We know that the United States is changing. Their trade relations, their foreign policy, their national monuments, their hydronyms,” he wrote. “Canadian women and men also know that things must be called by their name, and this lake is called Lake Ontario – today and forever.”

When Trump took the White House in 2025, he signed a similar order that changed the Gulf of Mexico to the Gulf of America. Mexico has rejected the name change, arguing a single country cannot rename a shared body of international water.

It also led to a legal dispute between Mexico and tech giant Google, which renamed the gulf in its maps application. , external

In that case, Google Maps users in the US see “Gulf of America”, while those in Mexico see the “Gulf of Mexico”. Those in other countries see the “Gulf of Mexico (Gulf of America)”.

The White House at the time also blocked Associated Press reporters from presidential events over the news agency’s refusal to adopt the name “Gulf of America” in its coverage. The AP sued the Trump administration in response, and that legal battle is ongoing.

There is no universally recognized international body setting the names of international waters. While the US president has broad discretion over how his country officially recognises landmarks, other countries do not have to follow.

Trump’s latest order directs the US Department of the Interior to update the Geographic Names Information Service – the official repository of domestic geographic names in the US – to reflect the name change, the president said.

Canada, however, does not have to recognise name changes made by other countries and officials have dismissed the idea.

Premier of Nova Scotia Tim Houston said on Thursday, “We’re into some real foolishness now. It’s Lake Ontario, buddy.”

“We’ll always call it Lake Ontario,” said Industry Minister Melanie Joly on Tuesday.

The names of four of the Great Lakes – Ontario, Huron, Michigan and Erie – originate from indigenous words. Lake Superior was named after an anglicised French word. Lake Ontario, the smallest of the Great Lakes, borders both the Canadian province and the US state of New York.

As he signed the order on Thursday in the Oval Office, Trump said it wasn’t a direct message to Canada, but that America’s northern neighbour “has been ripping us off for a long time on trade”.

Trump said he’d been thinking about renaming the lake “for a long time”.

“So if you think about it, we have a gulf and we have a lake,” Trump said.

“Now, all we need is an ocean. So maybe we’ll have to change the name of the Atlantic and or the Pacific. Maybe we’ll change them both.”

The name change request comes amid a trade dispute that has seen US-Canada relations fall to new lows, with insults thrown back-and-forth between the Trump administration and Canadian officials over the past week.

There was a hint on Thursday that there was room for a return to the negotiating table sometime in the future.

Canadian US trade minister, Dominic LeBlanc, said in a post on X that the US had withdrawn some of its demands around labelling requirements in French “and is confirming that measures to promote French language and Canadian culture will not be subject to future US trade actions”.

“We look forward to further constructive US clarifications on their other positions, which would create the possibility of a mutually beneficial trade agreement that respects Canadian sovereignty”.

Trade talks collapsed at the last minute late on Friday night, with both sides accusing the other of demanding last-minute changes to a tentative deal.