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. During high tide, it is partly under the water of the Potomac River, but during low tide you can venture out to the rocks to view it.
In all, 40 boundary stones were planted in the planning of Washington, DC, in a big square around the city.
Know Before You Go
You should go to the Park and head South across the paved walking area to the trail running next to the river. The markers aren't visible as of our visit 01.02.17