Several guides to place names in Pennsylvania have been published. Three of the most helpful are:
Day, Sherman. Historical Collections of the State of Pennsylvania: Containing a Copious Selection of the Most Interesting Facts, Traditions, Biographical Sketches, Anecdotes, etc., Relating to its History and Antiquities, Both General and Local, with Topographical Descriptions of Every County and all the Larger Towns in the State. (Philadelphia, PA : G. W. Gorton, [1843?] (New Haven, Ct.: Durrie and Peck ). Family History Library book 974.8 H2d; film 824413 item 1.)
Espenschade, Abraham H. Pennsylvania Place Names. 1925. Reprint, Baltimore, Maryland.: Genealogical Publishing, 1970. (Family History Library 974.8 E5e; film 1425647 item 5.)
Gordon, Thomas F. A Gazetteer of the State of Pennsylvania. Philadelphia, PA: T. Belknap, 1832. (Family History Library 974.8 E5g; film 543662 item 5; fiche 6053251.)
A recent guide is Pennsylvania Gazetteer(Wilmington, Delaware: American Historical Publications, 1989; Family History Library book 974.8 E5p). For some localities it includes important historical details.