Official State Nickname of Pennsylvania
Pennsylvania's nickname is "The Keystone State" because it was the middle colony of the original thirteen colonies, and because Pennsylvania has held a key position in the economic, social, and political development of the United States.Three of our most treasured documents were written in Pennsylvania: the US Constitution, the Declaration of independence, and the Gettysburg Address. All State Nicknames
What is a Keystone?
The word keystone is from architecture, it describes the central wedge-shaped stone in an arch which holds all the other stones in place.