Gulf of Mexico (12,425 ft) (3,787 meters)

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 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 km2 (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 km3 or 600,000 cu mi).

The Sigsbee Deep (Mexico basin in the U. S. Board on Geographic Names Advisory Committee on Undersea Features (ACUF) Gazetteer), is a roughly triangular basin that is the deepest part of the Gulf of Mexico.

The basin is located in the southwestern quadrant of the Gulf, with its closest point to the U.S. coast at 200 miles (320 km) southeast of Brownsville, Texas. The actual maximum depth is disputed and estimates range between 3,750 and 4,384 metres (12,303 and 14,383 ft). The average depth of the Gulf is roughly 1,615 metres (5,299 ft). The Sigsbee Abyssal Plain is the deepest and flattest sector of the deep basin.