Long after President Trump is gone, it will still be called Lake Ontario, said Doug Ford, premier of the Canadian province of Ontario, in a video on social media.
Wearing a football shirt, Ford unveiled the 26-square-metre sign in the town of Grimsby on Saturday.
Lake Ontario is one of the Great Lakes and stretches between the United States and Canada.
Donald Trump this week ordered the US to rename the lake, which is seen as part of the trade conflict with Canada. Similarly, last year he ordered the Gulf of Mexico to be renamed the Gulf of America.
Being mocked as a traitor
According to Ford, who is one of Trump's most vocal critics in Canada, the name change is because Trump cannot stand Canadians "standing up for themselves" and refusing to bow to his threats.
Wab Kinew, premier of the province of Manitoba, mocks Trump and likens him to a defunct rock star desperately trying to breathe life into 50-year-old hits.
"I think that's the part of Donald Trump's presidency we're in now. Like he thought they had a real deal, a real old deal, with the Gulf of Mexico," he said, according to the AP news agency.
And he's trying to find his way back, he's trying to play his hits for the fans. But I think everyone here thinks it's a little sad and that it's not his best work.
Condemned by indigenous people
The name Lake Ontario comes from the Huron indigenous word for, roughly, "sparkling water." The Canadian province of Ontario took its name from the lake when it was founded in 1867.
According to the AP, Trump's actions are condemned by Pierre Picard, leader of the Huron-Wendat Nation, as an attempt to "erase our history, our culture and our identity."
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