1:24,000 USGS DRG files are offered for all quadrangles in Illinois by file name in two projection and format combinations. The USGS Topographic Map Index (5.2 MB) can assist you in locating a quadrangle.
Alternative versions of some 1:24,000 USGS DRG files are offered as 500dpi USGS DRG files (metadata) and as Raster Color Composite (RCC) files in 500dpi or 1,000 dpi (metadata). There are a total of 217 500dpi DRG files; these are all that were created by USGS for the 500dpi scanning effort. There are 143 RCC files, these are all that have been created by USGS for Illinois to date.