Pennsylvania Geography
- Pennsylvania [Worldmark Encyclopedia of the States]via GVRL (Gale Virtual Reference Library).
- Soil Surveys for PennsylvaniaCounty soil surveys include a brief overview of regional geography.
Pennsylvania Spatial Data Access (PASDA) Resources
- Pennsylvania Spatial Data Access (PASDA) Imagery NavigatorThe PASDA Imagery Navigator provides access to the PASDA aerial photography collection via a search interface that displays all data available for any place in the state. Most of this collection is aerial orthoimagery and provides download access as well as streaming data services.
- PAMAP Digital Base Maps for PennsylvaniaThe PAMAP program was a collaboration among state agencies to produce a collection of statewide high resolution digital orthoimagery and lidar elevation data.
Maps and Aerial Photos
- County Formation MapsThis site shows changes in county boundaries over time.
- Historical Maps of PennsylvaniaThis site features images of maps of Pennsylvania from the 16th-20th centuries.
- Historic County Maps (of Pennsylvania)This site provides access to county transportation maps from the early 1900s to date.
- Penn PilotHistoric aerial photographs of Pennsylvania.
- TopoViewUSGS interface for finding topographic maps of the US. Zoom into PA to find topographic maps of Pennsylvania.