A comprehensive source of maps, geospatial and geostatistical data for the United States. The raw data that went into making the atlas can be downloaded freely for use in desktop GIS programs.
National Historical Geographic Information System (NHGIS)
The National Historical Geographic Information System. Provides "aggregate census data and GIS-compatible boundary files for the United States between 1790 and 2000." Free registration required.
((DEAD LINK--TO BE UPDATED)) National Geospatial Data Clearinghouse
Search 250 spatial data servers at once through a single interface.
((404 PAGE NOT FOUND--TO BE UPDATED)) North American Environmental Atlas
Harmonized base layers of Canada, Mexico, and the U.S., as well as layers of environmental data, from the Commission for Environmental Cooperation.
Toronto GIS Data -- City of Toronto Open Data Portal ((INFO ABOUT THIS WEBSITE TO BE UPDATED))
((DEAD LINK--TO BE UPDATED)) United Nations Environment Program GEO Data Portal
Data from UNEP's Global Environment Outlook (GEO) report, as well as other environmental and socioeconomic data.
