Sanford is a city in the U.S. state of Florida and the county seat of Seminole County. It is located in Central Florida and its population was 61,051 as of the 2020 census. Known as the "Historic Waterfront Gateway City", Sanford sits on the southern shore of Lake Monroe at the head of navigation on the St. Johns River. Native Americans first settled the area thousands of years before the city was formed. The Seminoles arrived in the area in the 18th century.