The Southwest No. 6 Boundary Marker of the Original District of Columbia is located in the median strip of South Jefferson Street between Columbia Pike and Leesburg Pike in Arlington County. The No. 6 mile marker was the second Virginia stone that was set at an uneven distance because the end of that mile of the boundary line was in a stream. Its original wrought iron protective fence was placed in 1916; by 1949 the fence was gone and the stone sat on the edge of a large gravel pit. Threatened by construction of roads and apartments, the Southwest No. 6 Boundary stone was removed and stored by Arlington County for three years. It was then placed in the middle of the median strip on South Jefferson Street, this being the closest public land next to its original site. It was given a new iron fence and rededicated in its new location in June 1965. The Southwest No. 6 Boundary Marker was listed under the Multiple Property Document (MPD) form for the Boundary Markers of the Original District of Columbia.