The purpose of the Greater Philadelphia GeoHistory Network is to gather geographic materials useful for the study of historic Philadelphia and its region. This site contains thousands of old maps, property atlases, city directories, industrial site surveys, and other items documenting the history, growth, and development of the city from the 1600s through today.

Drawing information from the field journals of Lewis and Clark, this project out of the University of Missouri also provides a reconstruction of the historical landscape

This research, education, and outreach project is dedicated to using new technology and archival data to recreate the survey W.E.B. Du Bois conducted of Philadelphia's Seventh Ward for his 1899 classic book, The Philadelphia Negro.

Project designed to track county boundary changes from the 1600s to the present.

Digitized maps and atlases from the collections of the New York Public Library.

11 collections of mostly US historical maps, including revolutionary and civil war era maps, as well as WWII Military Situation maps.