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 and replace the town meeting format with a city council/mayor/strong manager form of government, along with other changes. The new charter took effect on January 1, 2013. Sanford's new charter provides that the first mayor would be appointed from the ranks of Sanford's seven city councilors and serve interim for one-year period. On January 8, 2013, Maura A. Herlihy was appointed as Sanford's first mayor.In 2014, an elected-at-large mayor would take office and serve a three-year initial first term.