Although Swedes and Dutch were the first European settlers, the English Quaker William Penn named Pennsylvania for the Latin phrase meaning "Penn's Woods", in honor of his father. Penn's original choice of name had been "New Wales", as descriptions of the terrain and climate reminded him of Wales. The name was rejected due to protest from Welsh members of Parliament, who objected to the name of their region being applied to such a wild and uncivilized territory, especially one founded by Quakers. William Penn then suggested "Sylvania"- Latin for "woods" as an alternative. Charles II amended that name to "Pennsylvania". As the Quaker religion frowns on such acts of egotism, William Penn objected to the idea, but was placated by the King's proposal to name the state in honor of Admiral Sir William Penn- Penn's father and national hero, rather than William Penn himself. Today, two major cities dominate the state—Philadelphia, home of the Liberty Bell, Independence Hall, and a thriving metropolitan area, and Pittsburgh, a busy inland river port and major center for educational and technological advances. The Pocono Mountains and the Delaware Water Gap provide popular recreational activities.

Pennsylvania is one is one of four states to call itself a commonwealth; the others are Massachusetts, Virginia, and Kentucky. The battleship USS Pennsylvania, damaged at Pearl Harbor, was named in honor of this state, as were several other naval vessels. It was repaired at the former Sun Ship Yard & Dry Dock in Chester City. Rocks formed during the Pennsylvanian time period in geology (about 300 million years ago) are common in Pennsylvania. The epoch was named for the state.