A USAID-funded global archive of spatial data collected and distributed for the greater humanitarian community. While located at the University of Georgia, the GIST Repository is free to access but requires creation of a login account.
Contains links to webites with attribute and geospatial data for each of the 50 states, Washington, D.C., and the United States as a whole. This site is maintained by the University of Arkansas Libraries.
The National Geospatial Program provides leadership for USGS geospatial coordination, production and service activities. Access, view, and download information from geo-spatial databases produced by the USGS and other government agencies.
This is a wiki of publicly accessible U.S. state agency databases, hosted by the American Library Association (ALA) Government Documents Round Table (GODORT). Contains a lot of state specific, often overlooked data, that is maintained by local experts.