The District of Columbia's boundary stones are the 40 stone markers placed in the 1790s to form the borders of the new capitol district.
Most remain intact, and more than a few serve as inspiration for nearby geocaches.
This cache is near the SE5 boundary stone along Southern Avenue, which runs for about 7 miles and forms the border between D.C. and Prince George's County, Maryland.
The Southern Avenue metro stop, on the Green Line, is a few minutes walk away. The station also serves as a major MetroBus hub and has ample parking.
This cache does not require you to, and you should not, approach or cross any train tracks.