Mason City, city (1990 pop. 29,040), seat of Cerro Gordo co., N central Iowa; inc. 1874. It is the rail, trade, and industrial center of a large agricultural area. There is food processing and meatpacking; manufactures include cement, fertilizers, electrical goods, metal and paper products, and machinery. North Iowa Area Community College (1918) is the oldest in the state. A large band festival is held annually in Mason City.