Sanford is a city in York County, Maine, United States. The population was 20,798 in the 2010 census, making it the seventh largest municipality in the state. Situated on the Mousam River, Sanford includes the village of Springvale. The city features many lakes in wooded areas which attract campers. Sanford is part of the Portland–South Portland–Biddeford, Maine metropolitan statistical area. On November 6, 2012, Sanford voters approved a new charter to re-incorporate Sanford as a city ...