Piney Point was the Potomac River's first lighthouse, and one of four that still stand on the river. It was completed in 1836 and cost $5,000. Some of the sandstone used in construction came from the same Virginia quarry that supplied stone for the U. S. Capitol and the White House.
The light is no longer in service. The government gave it to St. Mary's County in 1980. Renovation began in 1990 on the crumbling structure. It reopened as a museum in 1995, illustrating a time when the Potomac acted as the region's highway.