The Ancestry Library Edition collection has approximately 4,000 databases including key collections such as U.S. Federal Census images and name indexes from 1790 to 1930; the Map Center containing more than 1,000 historical maps.
The Geohistory Network includes scanned images of historic fire insurance atlases and directories for Philadelphia. It is a pilot project of the Philadelphia Area Consortium of Special Collections Libraries (PACSCL) to develop a web-based repository of geographically organized historical information about Philadelphia, its geography, its buildings, and its people.
The Social Explorer produces maps and reports of US Census Tract level data from 1940-2000. Using high quality maps and data, they make available the full contents of the tract data for the United States for the full period. The data can also be exported as excel spreadsheets for easy reuse.