CANADA PRIME MINISTER Mark Carney has said that his country “know that naming reality means calling it Lake Ontario”, after Donald Trump ordered it to be renamed “Lake America”.

The name change order from the US president came as he escalated his trade war with Canada.

US-Canada trade talks collapsed at the last-minute last week, which prompted the two longtime allies to slap tit-for-tat tariffs on each other.

On Thursday, Trump signed an executive order changing the name of the body of water on the border between the North American neighbours.

“We’re going to be changing the name of Lake Ontario effective immediately to Lake America,” Trump told journalists as he signed the order at the White House.

Asked by a reporter why he was targeting an ally for punishment instead of America’s adversaries, Trump replied: “The Canadian officials have treated us very badly. They’re nasty people.”

Behind Trump’s desk in the Oval Office were two maps – one with the words “Lake America” in red over the lake, and the other with the header, “Making the Great Lakes Even Greater.”

Poster shows name change from Lake Ontario to Lake America, as Trump signs executive order on renaming in Oval Office of the White House Alamy Stock Photo Alamy Stock Photo

In a post on social media, Carney remarked that the name Lake Ontario “comes from the Wendat word Ontari’io”.

He said this “appropriately means “the lake is beautiful, the lake is big”.

Meanwhile, Carney noted that the name is over 400 years old and predates the formation of both the United States and Canada.

“We know that America is changing,” said Carney. “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.”

Lake Ontario is the smallest by surface area of the five Great Lakes, which straddle the border between the United States and Canada. It borders the Canadian province of Ontario and the US state of New York.

The name change mirrors Trump’s unilateral altering of the name of the Gulf of Mexico to the Gulf of America in January 2025 – a move Mexico has also rejected.

In Toronto, Canada’s largest city which lies on the lake’s northwestern shore, Canadians and Americans alike criticised Trump’s move.

“Typical Trump. He’s being a bully, he goads, he antagonizes,” said Mark Weicker, who lives in Kitchener, west of Toronto.

“He’s just trying to egg us on,” chimed in Jake Marchuk, who was visiting from Alberta province.

Megan Smith, who hails from New Jersey, put it bluntly: “It just makes him look stupid.”

Trump’s executive order meanwhile tells the US Department of the Interior to update references to the lake in the official geographical naming service within 30 days and ensure the federal government calls it “Lake America”.

It justified the name change by saying that the deepest part of the lake is on the American side, meaning that the US “claims most of the Lake’s volume.”

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 has even hinted at renaming oceans that border the US.

“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.”

-With additional reporting from © AFP 2022