President Trump signed an executive order Thursday seeking to rename Lake Ontario as Lake America, escalating a running dispute with Canada that has already produced new tariffs on both sides of the border.
Trump said the move was "official, effective immediately" and that his administration has "filed all the necessary papers, documents" to make the change. The text of the executive order directs the U.S. Department of the Interior to update the name with the Geographic Names Information Service, the official federal repository of domestic geographic names, within 30 days.
The order follows the collapse of trade talks between the U.S. and Canada late last week. The U.S. imposed new 50% tariffs on $20 billion worth of Canadian goods after negotiations broke down. Canada has announced it will implement dollar-for-dollar counter tariffs next month.
Trump had repeatedly threatened the name change on social media before signing the order. Lake Ontario is one of the five Great Lakes that straddle the U.S.-Canada border.
Canadian Prime Minister Mark Carney responded Thursday, noting that the name Lake Ontario dates back more than 400 years, predating both Canadian Confederation and the U.S. Declaration of Independence. In a social media post, Carney wrote: "We know that the United States is changing. Their trade relations, their foreign policy, their national monuments, their hydronyms. Canadian women and men also know that things must be called by their name, and this lake is called Lake Ontario – today and forever."
Ontario Premier Doug Ford was more direct, writing on social media, "It's Lake Ontario to Canadians and the rest of the world. Now and forever." Nova Scotia Premier Tim Houston wrote: "We're into some real foolishness now. It's Lake Ontario, buddy." Industry Minister Melanie Joly said Tuesday, "We'll always call it Lake Ontario."
Canada is not required to recognize name changes made by the United States, and officials there have said they will not. There is no universally recognized international body with authority over the naming of shared international waters.
The Lake Ontario order mirrors a move Trump made in 2025, when he signed a similar executive order renaming the Gulf of Mexico as the Gulf of America. Mexico rejected that name change, and it triggered a legal dispute with Google over how the company labeled the body of water in its maps. Under the current arrangement, Google Maps users in the U.S. see Gulf of America, those in Mexico see Gulf of Mexico, and users in other countries see both names. The White House also blocked Associated Press reporters from presidential events after the outlet refused to adopt the new name. The AP sued the administration, and that case remains in litigation.
