Can Trump change the name of the Gulf of Mexico? Maybe, but it’s not a unilateral decision, and other countries don’t have to go along. The International Hydrographic Organization — of which both the US and Mexico are members — works to ensure all the world’s seas, oceans and navigable waters are surveyed and charted uniformly, and also names some of them. There are instances where countries refer to the same body of water or landmark by different names in their own documentation.
I found this paragraph…
From this webpage… https://www.pbs.org/newshour/politics/can-trump-change-the-name-of-the-gulf-of-mexico-to-gulf-of-america