Illinois Geologic Quadrangle (IGQ) Maps
Most Illinois Geologic Quadrangle (IGQ) maps originally were produced as STATEMAP or Illinois Preliminary Geologic Map products; some were derived from other mapping activity. In addition to bedrock and surficial geology, this series may include a variety of geologic themes such as bedrock topography, drift thickness, and others. IGQ maps are available for sale as hard copy and as free downloadable graphics through this website. Digital (GIS) data are available for some of these geologic maps. They are extensively reviewed, internally and externally, and comply with ISGS cartographic standards at the time of public release.
Other ISGS map Series
Updated 10/5/2009 JKH
