National City, city (1990 pop. 54,249), San Diego co., S Calif., on San Diego Bay; inc. 1887. Structural metal is fabricated, and there is shipbuilding and the manufacture of recycling machinery, plastics, transportation equipment, electrical and electronic products, signs, furniture, and clothing. The city saw a steady growth in population in the late 20th cent. It serves as the headquarters of the Pacific Reserve Fleet.