The South Boundary Stone is America’s first federal monument, laid in 1791 by Benjamin Banneker as part of a surveying project to outline the newly created District of Columbia.
The stone now resides in the sea wall separating Jones Point Park from the Potomac River. To find the stone, simply follow the trails marked to the Jones Point Lighthouse. The stone sits between the lighthouse steps and the fence by the Potomac Ruverin, buried under a square bronze-and-glass covering.
Other newer boundary stones and a USGS marker extend in both directions behind the lighthouse, with the boundary line noted on top of each and the words District of Columbia, Maryland, and Virginia engraved on the sides. In all, 40 boundary stones were planted in the planning of Washington, DC, in a big square around the city.
While many of the border stones have been lost, the north, east, and west corner stones are still intact.