Casco is a census-designated place (CDP) in the town of Casco in Cumberland County, Maine, United States. The population of the CDP was 587 at the 2010 census. It is part of the Portland–South Portland–Biddeford, Maine Metropolitan Statistical Area.
According to the United States Census Bureau, the CDP has a total area of , of which is land and , or 7.28%, is water. It is located along Maine State Route 121 near the northern corner of the town of Casco, at the outlet of Pleasant Lake.