Mobile Bay, arm of the Gulf of Mexico, SW Ala., from 8 to 18 mi (12.9–29 km) wide, extending c.35 mi (56 km) from the Gulf to the mouth of the Mobile River. A ship channel connects Mobile Bay with the Gulf. The Intracoastal Waterway passes through the southern part of the bay. Mobile, Ala., is on the northwest shore. Admiral David Farragut, a Civil War naval hero, won the celebrated battle of Mobile Bay on Aug. 5, 1864.