<Tr> <Th> Settlements </Th> <Td> Houston, New Orleans, 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, or sometimes the "south coast", in juxtaposition to the Great Lakes region being the "north coast ." One of the gulf's seven main areas is the Gulf of Mexico basin . </P> <P> The Gulf of Mexico formed approximately 300 million years ago as a result of plate tectonics . The Gulf's 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 (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). </P> <P> The International Hydrographic Organization defines the southeast limit of the Gulf of Mexico as follows: </P>

Where does the gulf and atlantic ocean meet