World War II also brought the opening of a major military post, MacDill Air Force Base. Tampa has remained a city of families and young people, a place with a blue-collar past which is quickly moving upscale as it expands. The Tampa economy has steadily grown over the years. Tampa is the county seat of Hillsborough County and the third most populous city in Florida. Hillsborough is Florida's fifth most populous county.
Incorporated cities are Tampa, Temple Terrace and Plant City.
Major unincorporated areas are Brandon, Ruskin, Apollo Beach, Dover, Valrico and Sun City Center. The 11th Congressional District consists of Tampa and two-thirds of Hillsborough County. In 1990, there were 562,293 living in the 11th District.