A Selection of sites for GIS Data Sources

The Connecticut Department of Environmental Protection provides GIS data for Connecticut available for download.  GIS feature data is in Shapefile format and raster data (imagery) is in MrSid format. 

Massachusetts Geographic Information systems from the Commonwealth's Office of Geographic and Environmental Information.

The Rhode Island Geographic Information System

USGS Studies in Long Island Sound from the Coastal and Marine Geology Program.  

US Census Bureau which provides a variety of census data and maps form the 2000 Census and some historical data  For more historical census data visit Historical Census Browser at UVA or IPUMS at U of MN.

Geodata explorer, a discover tool for GIS data from the USGS.

Starting the Hunt: Guide To Mostly On-line And Mostly Free U.S. Geospatial Data from the University of Arkansas Library.