Data archive for spatial pattern analysis

• AI-GEOSTATS: A European Union Directorate General web service for geostatistical and spatial statistics
  
• Census Bureau Factfinder: Free decennial census population and social characteristics data
  
• Center for International Earth Science Information Network (CIESIN): Clearinghouse for environmental data, metadata, and data tools
  
• Digital Chart of the World Server (Penn State): International boundary files
  
• Geography Network: Clearinghouse for free and fee-based geographic data
  
• GeoStat: Geospatial and Statistical Data Center at the University of Virginia
  
• GIA Core at Penn State's Population Research Institute: houses an array of geospatial data holdings on international and US topics
  
• National Historical Geographic Information System: NHGIS is a project to create and freely disseminate databases incorporating all available aggregate census information for the United States between 1790 and 2000 in a format for GIS processing
  
• Social Explorer: Produce and visualize interactive maps using US Census data for different geographic units from 1870 to 2000
  
• SAL Data: Sample data for teaching and research with GeoDa from the Spatial Analysis Lab at the University of Illinois
• USGS National Geospatial Data Clearinghouse: Geospatial data from the US Geological Survey

(The list is compiled by CSISS.)