Which U.S. state has the nickname "The Keystone State"?

Pennsylvania is referred to as "The Keystone State" due to its central location among the original thirteen colonies and its pivotal role in the founding of the United States. The term "keystone" historically indicates a vital component that holds other elements together, much like Pennsylvania's significance in early American history and its geographical position. The state was a crucial meeting point for both commerce and communication, impacting the development of the nation.

The nickname highlights Pennsylvania's importance in various aspects, such as politics, economics, and transportation. This centrality is metaphorically akin to the keystone in an arch, which is essential for stability.

Other states like New York, Virginia, and Ohio, while significant in their own right, do not carry the moniker of "The Keystone State" and have different historical and geographical distinctions that contribute to their identities.