Gulf of Mexico Gulf of Mexico The Gulf of Mexico () is an ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. The U.S. states of Texas, Louisiana, Mississippi, Alabama, and Florida border the Gulf on the north, which are often referred to as the "Third Coast", in comparison with the U.S. Atlantic and Pacific coasts. The Gulf of Mexico formed approximately 300 million years
Gulf of Mexico origin for the Gulf of Mexico at the close of the Permian, which could have caused the Permian–Triassic extinction event. However, Gulf Coast geologists do not regard this hypothesis as having any credibility. Instead they overwhelmingly accept plate tectonics, not an asteroid impact, as having created the Gulf of Mexico as illustrated by papers authored by Kevin Mickus and others. This hypothesis is not to be confused with the Chicxulub Crater, a large impact crater on the coast of the Gulf of Mexico on the Yucatán Peninsula. Increasingly, the Gulf of Mexico is regarded as a backarc basin behind the