South San Francisco, city (1990 pop. 54,312), San Mateo co., W Calif.; inc. 1908. South San Francisco has several industrial parks; its manufactures include medical supplies and equipment, foods, paint, paper products, consumer goods, and clothing. The city's founding and growth were spurred in the late 19th cent. by the cattle-ranching and meatpacking industries. Nearby is San Francisco International Airport.