Climate
- United States Daily Weather Maps Project
- Historical daily weather maps from 1871 thru 2002 and a link to more recent daily weather maps.
- El Niño Page (National Oceanic and Atmospheric Administration)
- National Climatic Data Center (National Oceanic and Atmospheric Administration)
Land
- United States Geological Survey
- Focuses on Ecosystems, Geology, and Climate and Land Use
Species
- Endangered Species Program
- Includes information on threatened and endangered animals and plants. See also the local offices of the U.S. Fish & Wildlife Services.
Water
- Water Resources of the United States
- Includes the Water Data for the Nation, which provides access to years of historical and real-time water data collected by the U. S. Geological Survey.
General
- Science Inventory
- A searchable database of Environmental Protection Agency science activities and scientific/technical work products.
- Science.gov
- A gateway to authoritative selected science information provided by U.S. Government agencies, including research and development results.