Big Pool is an unincorporated community in western Washington County, Maryland, USA. Its population was 82 as of the 2010 census. It is between Clear Spring, Maryland and Hancock, Maryland along U.S. Route 40 and is officially a part of the Hagerstown Metropolitan Area.To the south of Big Pool lies Fort Frederick State Park, a restored fort used during the French and Indian War. Also nearby is the Chesapeake and Ohio Canal National Historical Park, which lies near Ft. Frederick alongside the Potomac River.Big Pool is also the name of a large body of water which is part of the Chesapeake and Ohio Canal. This pool occurs roughly at the 113 mile mark, and it is on what the canallers called the 14 mile level.