arm of the Gulf of Mexico (Mexico, Gulf of), extending 35 miles (56 km) north from its outlet to the mouth of the Mobile River in southwestern Alabama, U.S. It is 8–18 miles (13–29 km) wide and has a dredged channel (45 feet 【14 metres】 deep, 300–500 feet 【90–150 metres】 wide) that enters the Gulf between Dauphin Island and Mobile Point. Commercial traffic uses the Black Warrior–Tombigbee river system for travel north between the cities of Mobile (on the bay's northwestern shore) and Birmingham and the Intracoastal Waterway for travel east and west along the Gulf of Mexico. The bay was the scene of an American Civil War naval battle (August 5–23, 1864) in which the Union admiral David Farragut (Farragut, David) ran a blockade of mines, dispersed the Confederate fleet, and secured surrender of the forts defending the bay, including the strongest—Fort Morgan at Mobile Point.