AirNow: Air Quality Index
Maps and other data from federal, state, and local government agencies.

Center for International Earth Science Information Network
Interdisciplinary research on human interactions in the environment including populations, sustainability, use of spatial data, climates, etc. From Columbia University.

Environmental Protection Agency (EPA)
Writes and enforces regulations relating to human health and the environment. Set national standards that states and tribes enforce through their own regulations.

EPA New England Office
Environmental information for New England region.

EPA National Library Network
Provides information resources and services to EPA staff and the public

EPA's data warehouse.

View and query environmental information including drinking water, toxic and air releases, hazardous waste, water discharge permits, and Superfund sites.

Environmental Data Explorer
Datasets and other information used by UN Environment Programme and its partners. Data can be viewed online as maps, graphs or tables, or downloaded.

Global Biodiversity Information Facility
Free and open access to biodiversity data.

Major Environmental Laws & Regulations
Summaries and full text of laws and regulations under which EPA operates.

National Service Center for Environmental Publications (NSCEP)
Site for free EPA print and digital documents

Natural Resources Conservation Service (NRCS) Technical Resources
US Department of Agriculture NRCS tools for research in soils, water resources, air quality, and other conservation tools.

Piscataqua Region Estuaries Partnership
Part of the EPA's National Estuary Program, the NEP is a joint local/state/federal program established under the Clean Water Act with the goal of promoting the protection and enhancement of estuarine resources identified to be of national significance.

Renewable Resource Data Center
Information, data, and maps on biomass, solar, geothermal, and wind energy.

Socioeconomic Data and Applications Center (SEDAC)
Thematic guides to selected environmental issues.

Superfund Enterprise Management System
Lists and describes the most serious Superfund sites identified for possible long-term cleanup on the National Priorities List (NPL).

United Nations Environment Programme

US Fish & Wildlife Service

US Forest Service

US Geological Survey

Surf Your Watershed: Watershed Info from EPA

World Resources Institute
Documents sorted geographically and by subject area.