As part of our continuing efforts to increase awareness of and access to geospatial data and services, Data.gov has integrated the Geospatial One-Stop (GOS) portal and catalog, and added some exciting improvements to both the user interface as well as the underlying infrastructure.
Web portal for geospatial data produced by most federal agencies. Data categories include agriculture, demographic, environment, orthophoto and imagery, transportation, business and many others. Provides external links to some sources.
Data download interface for National Atlas data sets. Nearly all data available in the National Atlas Map Maker can be downloaded free through this site. Data categories include agriculture, biography, boundaries, climate, environment, history and geology.
Population, housing and economic data sets from the U.S. Census. currently covering 1950-presnet. This ongoing project is working to provide earlier data, ultimately back to 1790. Free. Registration required.