The TIGER/line files

The U.S. Geological Survey's TIGER/line files constitute a digital base map of the entire United States. These files include spatial data for such geographic features as roads, railroads, waterways, and political and census boundaries (e.g., boundaries of tracts and block groups).

The Tiger/line files are available in several editions. The Map Collection and most depository libraries have copies of each of these editions; you may copy them freely.

The TIGER/line files themselves cannot, unfortunately, be used by most commercial mapping programs. You need to convert them into the appropriate format. This can be done by such programs as TGR2SHP (for ArcView shapefiles), TGR2MIF (for MapInfo .mif files). You can also download certain editions of these files from various sites. ESRI will let you download a nearly complete version of Tiger-based shapefiles. CAGIS (the Chicago Area Geographic Information Study) maintains a site from which you can download Illinois TIGER/line files.