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 ). FHL book 974.8 H2d and FHL film 824413 item 1
A recent guide is Pennsylvania Gazetteer(Wilmington, Delaware: American Historical Publications, 1989; Family History Library book FHL book 974.8 E5p For some localities it includes important historical details.