Sheffield, industrial city (1990 pop. 10,380), Colbert co., NW Ala., on the Tennessee River near Muscle Shoals, in an iron and coal area; inc. 1885. Its varied manufactures include aluminum products, metals, structural castings, rolled rubber, and motor vehicle parts. Nearby Wilson Dam (1925) supplies power for the area's industries and has one of the world's highest single-lift locks. The home of Helen Keller is in nearby Tuscumbia.