PENNSYLVANIA (WHTM) — The keystone is both an iconic symbol for Pennsylvania and part of its nickname, but why is Pennsylvania called the Keystone State?

According to, “keystone” is an architectural term that refers to the central, wedge-shaped stone in an arch. This stone holds all other stones in the arch in place and is generally considered the most crucial part of an arch.

Pennsylvania holds the nickname “the Keystone State” because of its historic geographic, economic, and political position during the early days of the nation.

The keystone can be seen in Pennsylvania state agency logos which are printed on road signs, billboards, and more across the Commonwealth.

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But while the Keystone State was founded in 1787, its iconic symbol is far older.

According to Arizona State University, the Roman civilization was the first to use the keystone, also called a capstone, in arches between 1000 B.C.E. and 500 C.E.

Nowadays they keystone can also be found on the sleeves of Pennsylvania State Police and other state government officials.