Concerted Effort Underway to Publish the State’s Geologic Maps


The ISGS has made a concerted effort to quickly publish, archive, and distribute geologic maps at quadrangle, county, regional, and statewide scales. Particularly since 2004, when review and map production protocols, including cartographic standards, were streamlined, the ISGS has published 176 geologic maps in formal map series—103 Illinois Geologic Quadrangles (1:24,000), 56 Illinois Preliminary Geologic Quadrangles (1:24,000), 12 Illinois County Geological Maps (mainly 1:100,000), and 5 I-Maps (1:100,000 or smaller). An additional 70 maps from contract reports and bulletins have been made available for online viewing and delivery—46 backlogged STATEMAP quadrangles that are awaiting formal review and 24 maps from historical ISGS bulletins. The map publishing exercise represents ongoing efforts through programs such as STATEMAP and to use data from older studies that had not been formally published. Maps are available online from the ISGS website in PDF format, with the option to download the GIS data.