Trump orders Lake Ontario renamed Lake America as Canada holds the old name

President Donald Trump signed an executive order on Thursday directing the U.S. Department of the Interior to stop using the name Lake Ontario on federal maps, contracts and databases. The replacement name is Lake America. He told reporters in the Oval Office that the change was official and effective immediately, and that the administration had filed the papers required to rewrite the Geographic Names Information System within 30 days.

The order applies only to how the United States government refers to the lake. It does not bind Canada, New York State, the International Hydrographic Organization, shipping charts or commercial mapmakers. About 52 percent of the lake surface area lies in Canada. The remainder sits in New York. An administration official argued that most of the water volume and the deepest basin fall on the American side. That claim does not change the legal status of an international water body whose shoreline, ports and fisheries are split between two countries.

Trump first floated the idea on Truth Social on Tuesday, writing that the United States did not expect to do much business with Ontario any longer. On Wednesday he posted a video of himself crossing out Lake Ontario on a map and writing Lake America by hand. On Thursday an easel in the Oval Office carried a Great Lakes map under the slogan Making the Great Lakes Even Greater, with the new label already printed over the easternmost lake. White House staff secretary Ben Moss told him the lake once known as Lake Ontario would from this day forward be known as Lake America.

A name older than both countries

The name Ontario comes from an Iroquoian phrase often rendered as Ontari'io, lake of shining waters. European maps began using versions of it in the 1660s. Canadian Prime Minister Mark Carney noted on Thursday that the name predates Canadian Confederation and the U.S. Declaration of Independence. In a post that went up before Trump signed the order, Carney wrote that Canadians know naming reality means calling it Lake Ontario, then, now and always.

New York Governor Kathy Hochul was shorter. New York will not be calling it that, she wrote. Nova Scotia Premier Tim Houston called the move real foolishness. There is no single international court that assigns names to shared lakes. Other countries can ignore a U.S. gazetteer change, just as many mapmakers still print Gulf of Mexico after Trump renamed that body the Gulf of America on the first day of his second term.

Trump compared the two acts himself. We have a gulf and we have a lake, now all we need is an ocean, he said. Maybe we will have to change the name of the Atlantic and/or the Pacific. He added that the lake change was something he had been thinking about for a long time.

The trade fight that produced the order

The signing came days after U.S.-Canada trade talks collapsed and Washington imposed 50 percent tariffs on about $20 billion of Canadian goods. Ottawa has said it will answer with dollar-for-dollar counter-tariffs next month. Ontario is Canada's most populous province and the industrial core of the auto, steel and parts trade that now sits under those duties. Trump's posts treated the lake's name as a bargaining chip in that fight rather than a cartographic correction.

Interior Secretary Doug Burgum and the U.S. Board on Geographic Names are instructed to update the official domestic names database, remove references to Lake Ontario consistent with applicable law, and issue guidance so that executive departments use Lake America on maps, contracts and correspondence. Changing a geographic name normally runs through a public review. The Gulf of America order last year showed that a president can compress that process when the target is a federal label rather than a physical feature.

Ports on both shores will keep their existing names. Toronto, Hamilton, Rochester and Oswego do not change. The St. Lawrence River still drains the lake to the Atlantic. Shipping companies that file with both Canadian and U.S. authorities will now face two official names for the same water. Pilots, weather services and search-and-rescue desks already work across that border every day. They will have to decide which label they speak when a distress call comes in.

The practical test arrives when the first federal contract, weather product or Corps of Engineers notice prints Lake America and a Canadian partner replies with Lake Ontario. Neither government has said how it will handle that mismatch. Carney is due to address the European Parliament in mid-September after walking out of talks with Trump. The lake's name is a small file in that larger break. It is also the file that every school atlas on the American side will be asked to reprint.