Can Trump rename Lake Ontario to Lake America? Here's what to know

President Donald Trump signed an executive order on Thursday officially renaming Lake Ontario to “Lake America.”

“We’re going to be changing the name of Lake Ontario, effective immediately to Lake America,” Trump said in the Oval Office before signing the order. He used a marker to scratch out “Lake Ontario” on a map and replace it with “Lake America.”

The name change comes amid a brewing trade war between the U.S. and Canada. On August 24, Trump announced a 50 percent tariff on Canadian steel, auto parts, and vehicles. The U.S. and Canada met to negotiate a trade deal, but those talks broke down after which Canadian Prime Minister Mark Carney announced a “dollar for dollar” tariff on approximately 900 American-made goods.

Trump had threatened to rename Lake Ontario — one of the Great Lakes — earlier this week and followed through on Thursday.

But what does it actually mean that Trump renamed the lake, and who has to acknowledge the name change?

Trump has the power to force federal agencies to acknowledge the name. That means maps produced by agencies like the NOAA, the U.S. Geological Survey, or the Army Corps of Engineers will have to adhere to the “Lake America” name, just as they had to adhere to Trump’s decision to rename the Gulf of Mexico to the “Gulf of America.”

Doug Burgum, the Secretary of the Interior, indicated on Thursday he was ready and willing to comply with Trump’s new name.

“We’re on it, Mr. President! The places and waters that border our nation and support our economy should reflect the greatness of the United States. @USGS maps our country for the world to see, and we are PROUD to implement your Executive Order to rename LAKE AMERICA,” he wrote on X.

Beyond forcing federal entities to change the name on federal maps and documents, few others have to acknowledge the name change. Foreign governments have no obligation to call Lake Ontario “Lake America,” nor do any private entities. Trump learned that directly when the Associated Press refused to refer to the Gulf of Mexico as the Gulf of America after he changed the name.

Even U.S. states can ignore Trump’s order, as they are not beholden to the U.S. Board on Geographic Names, which oversees the names of geographic locations for federal agencies.

Trump hinted on Thursday that he may not be done slapping the word “America” on geographic locations.

“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 both,” he said.

When he was asked what message he wanted to send by renaming the lake to Lake America, he said “no message,” before launching into a rant about Canada “ripping off” the U.S.

“Canada has been ripping us off for a long time on trade,” he said. “They don’t pay for anything, and they want to be treated like a state, but they’re not a state.”

Shortly after taking office for his second term in 2025, Trump followed through on his promise to rename the Gulf of Mexico the “Gulf of America.”

In February 2025, the Board on Geographic Names formally changed the name of the body of water to the “Gulf of America.” Trump also ordered Denali — the highest mountain in North America — to return to its previous moniker, Mount McKinley.

On Super Bowl Sunday of that year, Trump flew over the gulf in Air Force One and declared it the first-ever “Gulf of America Day.”

Both Google Maps and Apple Maps updated the name on their apps shortly after the announcement.

The Trump White House couldn’t force media outlets to recognize the name change, so he punished them instead; the Associated Press said at the time that one of its reporters was barred from a Trump event because the wire service did not refer to the gulf as the “Gulf of America” in one of its stories.

Despite the fact that the gulf is shared by multiple nations, Trump insisted that the U.S. does the “most work” on the gulf, and said that the body of water should bear America’s name “because it’s ours.”

While ownership is up for debate, it’s true that the U.S. has claimed control over much of the gulf. The UN Convention on the Law of the Sea determined that U.S. territorial waters expand for 12 nautical miles from its shores, and the U.S. federal government manages the seas and the submerged parts of the Outer Continental Shelf as well.

Trump’s decision to rename the gulf was be part of a broader offensive against Mexico, which he’s called “very dangerous” and “in a lot of trouble,” citing drug trafficking and illegal immigration. However, most drug trafficking from Mexico is aimed at fulfilling consumer demand from Americans.

Mexican President Claudia Sheinbaum Pardo said at the time that she would ignore Trump’s executive order, and urged other world leaders to do the same.