USGS Geologic Map viewer and data download

Published Colorado geologic Maps are available for free download through the United States Geological Survey (USGS) National Geologic Map Database (NGMD).

The National USGS MapViewer

The State of Colorado on the USGS MapViewer

In the fall of each year, the CGS submits newly-produced geologic maps to the USGS NGMD via the STATEMAP Program.