National Geospatial Program
Federal Geospatial Portal to find data or map services, make a map, browse community information, and more.
USGS The National Map to view and download world geospatial information.
National Elevation Dataset for high resolution US elevation data.
USDA Geospatial Data Gateway for natural resource and environmental data.
The National Atlas for customizable maps as well as data for mapping professionals.
Integrated Taxonomic Information System provides authoritative taxonomic information on plants, animals, fungi and microbes including the locations of these organisms on Earth.
Open Geospatial Consortium a non-profit, international, voluntary consensus standards organization that is leading the development of standards for geospatial and location based services.