US PRESIDENT DONALD Trump announced Thursday that he is renaming Lake Ontario – a large body of water shared by the United States and Canada – “Lake America.”

Trump signed an order in the White House in a move that comes amid a spiralling trade war between the neighbours.

On Tuesday, Canada announced retaliatory tariffs on about $20bn (€17.15 billion) worth of American goods after the Trump administration imposed 50% tariffs over the weekend on Canadian goods following the collapse of trade negotiations.

Trump intensified the confrontation at the time by saying the US was giving “serious consideration” to renaming Lake Ontario “Lake America”.

The lake, which is one of the five Great Lakes of North America, shares a name with the Canadian province of Ontario.

The Canada–US border spans the centre of the lake.

A poster shows the name change from Lake Ontario to Lake America, as US President Donald Trump signs an executive order on the renaming in the Oval Office of the White House in Washington, DC. Alamy Stock Photo Alamy Stock Photo

Trump told reporters in the Oval Office today that the change will be “effective immediately”.

“The Canadian officials have treated us very badly. They’re nasty people,” he said.

A poster displaying the name change from Lake Ontario to Lake America was in the Oval Office as Trump signed the executive order.

The name change – which Canada is unlikely to accept – mirrors Trump’s changing of the name of the Gulf of Mexico to the Gulf of America in January 2025.

BREAKING: President Trump officially changes the name of Lake Ontario to Lake America.

"If you think about it, we have a gulf and we have a lake. Now, all we need is an ocean." 👀 🇺🇸 pic.twitter.com/OZOmfibisP

— The White House (@WhiteHouse) August 27, 2026

Trump said today he has been thinking of the change “for a long time”.

“As you know, we took something called the Gulf of Mexico, we changed it, and now it’s very routinely the Gulf of America,” he added.

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

Canadian Prime Minister Mark Carney uploaded a post on X this evening addressing the announcement.

“The name Lake Ontario comes from the Wendat word Ontari’io, which, appropriately, means ‘the lake is beautiful, the lake is big,’” he said.

He said the name is over 400 years old, predating the Confederation of Canada and the US Declaration of Independence.

“We know that America is changing. Their trading relationships, their foreign policies, their national monuments, their hydronyms,” Carney said.

“Canadians also know that naming reality means calling it Lake Ontario – then, now and always.”

With additional reporting from AFP.