http://tags.library.upenn.edu/tag/GIS+historic PennTags Feed http://tags.library.upenn.edu/makerecord/url/29864 http://tags.library.upenn.edu/makerecord/url/29864 <p>Shapefiles and data at the census tract, county, state, and other geographic levels going back to 1790 for counties, and 1910 for tracts. Also includes some data for downloading.</p> http://tags.library.upenn.edu/makerecord/url/20150 http://tags.library.upenn.edu/makerecord/url/20150 Shapefiles and data at the census tract, county, state, and other geographic levels going back to 1790 for counties, and 1910 for tracts. Also includes some data for downloading.