Delaware Maryland Pennsylvania Tripoint, Delaware

This is a point where you could be in three states at once. It is one of 35 points in the USA where three state lines meet on land (another 27 are in water). This point is marked with a stone monument. It is the northwest corner of a piece of land, around a square mile in size, known as the Delaware Wedge, which was in dispute for more than a century. ¾ of a mile west of this tripoint, the boundary between Delaware and Pennsylvania takes on the form of a portion of a circle, known as the Twelve Mile Circle, as its radius is the town of New Castle, 12 miles away. Due to a surveying error that was not detected for some time, this circle did not meet the boundary of Pennsylvania and Maryland as intended, creating a wedge of Pennsylvania that extended south, for three miles, until the arc of the circle met the eastern end of Maryland. This territory was claimed by both Pennsylvania and Delaware, until the matter was settled, granting it to Delaware, in 1921.