Google has updated its maps application to rename Lake Ontario as "Lake America" for users in the US.
It comes after Donald Trump ordered the name to be changed amid an escalating trade war with Canada.
The Canadian province of Ontario is on the lake's north, west and southwest, while New York state is on its southern and eastern shore.
President Trump made a similar proclamation in 2025, saying the Gulf of Mexico should be known as the Gulf of America. Google now marks it as "Gulf of Mexico (Gulf of America)".
The company said the decision to retitle the lake was because the US government's Geographic Names Information System (GNIS) had now formally changed the name.
"People using Maps in the U.S will see 'Lake America,' those in Canada will continue to see 'Lake Ontario,' and those outside of the U.S. and Canada will see both names," Google said.
"These updates follow our long-standing policy for bodies of water with names that vary from country to country, and are starting to roll out now."
For UK users on Monday morning, it still appeared to be showing "Lake Ontario" only.
President Trump signed the executive order to rename the lake on Thursday and suggested he might not be done.
He told reporters at the White House: "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."
The move to rename the lake was - unsurprisingly - met with derision in Canada.
Canadian Prime Minister Mark Carney responded on X: "The name Lake Ontario comes from the Wendat word Ontari'io, which, appropriately, means 'the lake is beautiful, the lake is big'.
"The name is more than 400 years old, predating both the Confederation of Canada and the Declaration of Independence of the United States of America."
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(c) Sky News 2026: Google renames Lake Ontario as 'Lake America' for US users after Trump order
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