Gulf of Mexico numerous bays and smaller inlets. A number of rivers empty into the gulf, most notably the Mississippi River and Rio Grande in the northern gulf, and the Grijalva and Usumacinta rivers in the southern gulf. The land that forms the gulf's coast, including many long, narrow barrier islands, is almost uniformly low-lying and is characterized by marshes and swamps as well as stretches of sandy beach. The Gulf of Mexico is an excellent example of a passive margin. The continental shelf is quite wide at most points along the coast, most notably at the Florida and Yucatán Peninsulas. The shelf
Department of the Gulf Department of the Gulf The Department of the Gulf was a command of the United States Army in the nineteenth and early twentieth centuries and of the Confederate States Army during the Civil War. The department was constituted on February 23, 1862 when the United States War Department issued General Orders No. 20; the department consisted of "...all of the coast of the Gulf of Mexico west of Pensacola harbor, and so much of the Gulf States as may be occupied by the forces under Major General B.F. Butler." On March 20, 1862, Butler activated his command at Ship Island,