Trump officially signs order to rename Lake Ontario as trade war escalates further

Donald Trump has signed an order directing the US government to call Lake Ontario 'Lake America,' adding a new flashpoint to his increasingly tense relationship with Canada.

The president signed the order Thursday, August 27, directing federal agencies to use the new name in official documents and records.

But there is an important catch: the move only applies to the US government.

Canada is under no obligation to use Trump's preferred name, meaning the lake's existing name remains in use outside the scope of the president's order.

Trump's latest move echoes an earlier attempt during his second term to rename the Gulf of Mexico as the 'Gulf of America.'

As with that decision, the president can direct federal agencies on how they refer to places within the US government's jurisdiction, but cannot compel other countries or private citizens to adopt the terminology.

Donald Trump has once again fallen out with Canada. (Photo by Andrew Harnik/Getty Images)

Why did Trump rename Lake Ontario?

The order comes as Trump's trade dispute with Ottawa continues, with the president using the renaming as another way to assert an American claim over a landmark shared by the two countries.

Lake Ontario is one of the five Great Lakes situated along the US-Canada border.

Trump's order tells federal agencies to use 'Lake America' when referring to it in official records and documents.

The move follows Trump's previous effort to change the name of the Gulf of Mexico.

That decision similarly demonstrated the limits of presidential naming power: while the US government can establish how its own agencies identify geographical features, it cannot dictate what another sovereign country calls them.

Trump's order therefore does not change what Canadians are required to call Lake Ontario, nor does it force people on either side of the border to adopt the new terminology.

Donald Trump has also rejected claims from Canadian Prime Minister Mark Carney that the US had threatened Canada's use of French amid tensions linked to the countries' trade conflict.

Writing on Truth Social on Tuesday, Trump said suggestions that he would seek to influence the language Canadians speak were unfounded.

He described the accusation as a fabrication and criticised Carney as an ineffective leader trying to bolster support in Quebec.

Trump also stressed his appreciation for French-speaking Canadians, adding that he would never seek to interfere with their language.

US President Donald Trump has signed an executive order that aims to rename Lake Ontario to Lake America. (Photo by Jim WATSON / AFP via Getty Images)

Can Trump officially change Lake Ontario's name?

Trump does have authority to determine how the federal government refers to places and landmarks, according to the report.

That means US agencies can follow his instruction and use 'Lake America' in government documents and records.

But the order has no effect outside the United States. Canada can continue calling the body of water Lake Ontario, while individuals and organizations are likewise not required to follow the president's preferred name.