Delaware–Maryland–Pennsylvania Tri-State Point

The Delaware–Maryland–Pennsylvania Tri-State Point is the meeting of the northwestern corner of Delaware, the northeastern corner of Maryland, and the southern edge of Pennsylvania. A wooden marker was placed in 1765, by Charles Mason and Jeremiah Dixon, and was replaced with a stone marker in 1849.

Source: Wikipedia — Delaware–Maryland–Pennsylvania Tri-State Point (CC BY-SA 4.0)