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 ago as a result of plate tectonics. The Gulf of Mexico basin is roughly oval and is approximately wide and floored by sedimentary rocks and recent sediments. It is connected to part of the Atlantic Ocean through the Florida Straits between the U.S. and Cuba, and with the Caribbean Sea (with which it forms the American Mediterranean Sea) via the Yucatán Channel between Mexico and Cuba. With the narrow connection to the Atlantic, the Gulf experiences very small tidal ranges. The size of the Gulf basin is approximately 1.6 million km (615,000 sq mi). Almost half of the basin is