USEPA Region 2 GIS links
National Mapping Information from United States Geologic Survey (USGS).
Federal Geographic Data Committee
National Geodetic Survey
Water resources of the United States from USGS.
USEPA Region 5 FIELDS System
USEPA BASINS Data and Application
USGS Geo-Data Explorer
EnviroMapper from the USEPA allows you to map features across the US.
Digital Chart of the World 1:1,000,000 scale data world-wide from Penn State University.
