Gulf Of Mexico, a basin of the Atlantic ocean, enclosed by the United States, the West Indies, and Mexico, and measuring about 1,000 m. from E. to W. and 800 m. from N. to S.; area, about 700,000 sq. m. The states of Florida, Alabama, Mississippi, Louisiana, and Texas border upon it on the north, and the Mexican states of Tamaulipas, Vera Cruz, Tabasco, Campeachy, and Yucatan on the west and south. Its entrance, between Cape Sable at the extremity of the peninsula of Florida and Cape Catoche at the extremity of the peninsula of Yucatan, is about 450 m. in width; but midway across this mouth lies the island of Cuba, leaving a passage on either hand, viz.: the strait of Florida on the northeast, 125 m. wide, communicating with the Atlantic, and the channel of Yucatan on the southwest, communicating with the Caribbean sea, 115 m. wide. West of Yucatan extends the broad bay of Campeachy; on the coast of Texas are the bays of Corpus Christi, Aransas, Matagorda, and Galveston; in Louisiana are those of Vermilion, Atchafalaya, Barataria, Black, and Lake Borgne; in Alabama, Mobile bay; in Mississippi, Mississippi sound; and in Florida, Pensacola harbor, Appalachicola, Appalachee, Tampa, and Charlotte bays, and the bay of Ponce de Leon. Besides these, the coasts, being mostly low and marshy or sandy, are lined with numerous lagoons.
There are few islands except some small ones belonging to Yucatan, a number near the delta of the Mississippi, and the Florida keys. The most important rivers of the gulf are the Suwanee and Appalachicola in Florida; the Mobile in Alabama; the Pascagoula and Pearl in Mississippi; the Mississippi in Louisiana; the Sabine, Trinity, Brazos, Colorado, Nueces, and Rio Grande in Texas; and the Panuco, Coatzacoalcos, Tabasco, and Usumasinta in Mexico. These streams are nearly all obstructed by bars at their mouths, and there are very few good harbors. Havana. Mobile, and Galveston are the most important ports; and Campeachy and Vera Cruz are two of the principal shipping points. - The depth of the gulf is believed not to exceed three quarters of a mile. The reefs and shoals of the N. shore of Cuba and about the Florida keys render the passage into the Atlantic exceedingly intricate, but elsewhere there are few banks; the only large one lies about lat. 27° N., Ion. 86° W., 200 m. S. of Cape San Bias. Besides the N E. and S. E. trade winds which prevail in the gulf, it is visited by violent northers, which occur at intervals from October to May; in some years they terminate in April. The most remarkable phenomenon connected with the gulf of Mexico is the Gulf stream (see Atlantic Ocean*), which enters it by the channel of Yucatan, passes around it, and flows out by the Florida channel.
The temperature of the gulf water is 8] or 9° higher than that of the Atlantic ocean in the same latitude. In its centre are found large quantities of fucus natans or gulf weed, floating in parallel lines from S. S. F. to N. N. W.