Biddeford is a town in York County, Maine, United States. It is the largest town in the county, and is the sixth-largest in the state. It is the most southerly incorporated town in the state and the principal commercial center of York County. The population was 21,277 at the 2010 census. Twin town of Saco, Biddeford includes the resort community of Biddeford Pool, Fortunes Rocks and Granite Point.