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Nicknames

Since 1802, Pennsylvania has been known as the Keystone State, which remains the state's most popular and widely-used nickname. The nickname "Keystone State" originates with the agricultural and architectural term " keystone ", and is based on the central role that Pennsylvania played geographically and functionally among the original Thirteen Colonies from which the nation was established, the important founding documents, including the Declaration of Independence and U.S. Constitution, that were signed and ratified in Pennsylvania, and the early central role that Pennsylvania played in the nation's early manufacturing and agricultural economic development.

Less commonly, Pennsylvania is sometimes referred to as the Coal State, the Oil State, and the Steel State, each developed in recognition of the important role these respective industries played in the state in the 19th and 20th centuries. The State of Independence appears on several present road signs entering Pennsylvania from neighboring states.

Pennsylvania residents and those of surrounding states commonly refer to Pennsylvania by the state's abbreviation, PA.

While it is no longer in common use, Pennsylvania was historically sometimes referred to by the nickname Quaker State during the colonial era based on the influential role that William Penn and other Quakers played in establishing the first frame of government constitution for the Province of Pennsylvania that guaranteed liberty of conscience, which was a reflection of Penn's knowledge of the hostility Quakers confronted when they opposed religious rituals, taking oaths, violence, war, and military service, and what they viewed as ostentatious frippery.