South Berwick is a town in York County, Maine, United States. The population was 7,220 at the 2010 census. South Berwick is home to Berwick Academy, a private, co-educational university-preparatory day school founded in 1791.The town was set off from Berwick in 1814, followed by North Berwick in 1831. It is part of the Portland–South Portland–Biddeford, Maine metropolitan statistical area.