Includes datasets from the Berkeley Earth Surface Temperature Study, extending back for 250 years.

Natural resources datasets from states and counties which can be downloaded.

Find federal, state and local geographic datasets at this site.

A portal to millions of data records from all over the world on biodiversity, including benthic and marine organisms.

"The NHD is a comprehensive set of digital spatial data representing the surface water of the United States using common features such as lakes, ponds, streams, rivers, canals, and oceans. These data are designed to be used in general mapping and in the analysis of surface-water systems using geographic information systems (GIS)" (quoted from website).

Geographic datasets for national parks, forests, historic sites, etc.

More than 500 cryospheric data sets for researchers, from both satellite and ground observations.

NCEI hosts and provides public access to one of the most significant archives for environmental data on Earth. They provide over 37 petabytes of comprehensive atmospheric, coastal, oceanic, and geophysical data.

Various land use datasets from the Center for Sustainability and the Global Environment (SAGE) at the University of Wisconsin-Madison.