The Wedge is the portion of the border between Delaware and Pennsylvania, between The Twelve-Mile Circle and intersection the north-south and east-west portions of Mason-Dixon line.

When Mason & Dixon surveyed the western boundary of Delaware the line they ran northward from the midpoint of the Transpeninsular line did not quite meet The Twelve-Mile Circle. It ended up a little to the west. Ownership of this land was in dispute until 1921, when it was granted to Delaware.