<Tr> <Th> Surface area </Th> <Td> 1,550,000 km (600,000 sq mi) </Td> </Tr> <Tr> <Th> Settlements </Th> <Td> Houston, New Orleans, Corpus Christi, Tampa, Havana, Campeche, Mobile, Gulfport, Tampico, Key West </Td> </Tr> <P> The Gulf of Mexico (Spanish: Golfo de México) 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 . </P> <P> The Gulf of Mexico formed approximately 300 million years ago as a result of plate tectonics . The Gulf of Mexico basin is roughly oval and is approximately 810 nautical miles (1,500 km; 930 mi) 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 shallow continental shelf waters . The basin contains a volume of roughly 2,500 quadrillion liters (550 quadrillion Imperial gallons, 660 quadrillion US gallons, 2.5 million km or 600,000 cu mi). The Gulf of Mexico is one of the most important offshore petroleum production regions in the world, comprising one - sixth of the United States' total production . </P>

Is the gulf of mexico an ocean or sea