Tri-States Monument - Credit: Wikimedia Commons
The Tri-States Monument (also known as Tri-State Rock) is a granite monument that marks the tripoint of the state boundaries of New Jersey, New York, and Pennsylvania. It is at the northwestern end of the boundary between New Jersey and New York, the northern end of the boundary between New Jersey and Pennsylvania, and the eastern end of the boundary between New York and Pennsylvania. The monument is located at the confluence of the Delaware and Neversink rivers. This location is also known as Carpenter's Point. Read more on Wikipedia
Source: en.wikipedia.org