Public domain GIS data and Free GIS data repositories and clearinghouses.
Other Local Sources
A local source for EPA GIS data is Carmen Masó with the EPA.
Carmen Masó, GISP GIS Analyst
USEPA Region 5
Resource Management Division
Information Management Branch
Information Services Section
77 W Jackson, Mail Code MI-10J
Provided by the Map and Geospatial Round Table of the American Library Association, this provides specific current, and vetted geospatial resources and professional tools for the map and geospatial information librarian
This website provides GIS shapefiles and census data corresponding to the level of the geographic information that you request. So it is a one-stop center for basic GIS and demographics for all census years down to block group level where available. Free registration is required.
Portal to links for data at USGS, ESRI, EPA, Fish and Wildlife Wetlands, Agriculture's Soil conservation, FEMA flood and coastal barriers, Census Bureau, and assorted other links to Illinois data. You are directed to original data sites.
Many of the materials in this website are available for free download. Besides the US, the remainder of the Americas, Europe, and Asia Pacific. Beware of metadata issues and check for source of data in it.
In additon to maps and interactive mapping, this site has a variety of GIS files (base files, transportation, community areas, etc.) that can be downloaded and used freely. Note that no metadata is available.
MetroChicagoData.org brings interactive information and data from the City of Chicago, Cook County and the State of Illinois into one single, citizen-friendly interface. Search for keywords or browse a unified set of topics and categories.
Access Illinois GIS data sets and documentation (metadata) for ArcIMS Interactive Map Services, USGS digital topographic maps, aerial photography, orthoimagery, orthophotography, geology, land use, natural resources, and infrastructure. Illinois data sets and map data layers are available for download free of charge