Fort Pierce is a city in St. Lucie County, Florida, USA. It is also known as the Sunrise City, sister to San Francisco, California, the Sunset City. The population was 37,516 at the 2000 census. As of 2004, the population recorded by the U.S. Census Bureau is 37,959. It is the county seat of St. Lucie County. Fort Pierce apartments for rent comparison page shows most up to date rent information on Fort Pierce apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.