Mason and Dixon placed a wooden marker on the tri-point on June 6, 1765.

[1] At one point, the marker went missing, so Lt. Col. James Duncan Graham, of the U.S.

In 1892, W.C. Hodgkins was sent to resurvey the area, and he fixed the location of the marker.

He also set the Arc Corner Monument, part of the resolution of the Delaware Wedge.

In December 2011, Pennsylvania bought the land on the Pennsylvania side of the marker, while the Delaware and Maryland sides remained as private lands.