A drone shot of the layered Miocene basalts of the Grand Mesa Volcanic Field. The tan Green River Formation (Paleogene)—forming the hoodoos—is seen beneath talus accumulations at the base of the basalt flows, Lands End, Grand Mesa, Colorado, July 2017. Photo credit: Julian Chesnutt for the CGS.

Colorado Geological Survey

The Colorado Geological Survey (CGS) is a state government agency situated within the Colorado School of Mines. We provide a wide range of science-driven services—this website being one—bringing the best of Colorado geoscience to the public.

Our Mission

To help reduce the impact of geologic hazards on the citizens of Colorado; to promote responsible economic development of mineral and energy resources; to provide geologic insight into water resources; and to proffer sound geologic advice and information to a variety of constituencies.

More about the CGS

Stock groundwater well, Lost Creek Basin, Weld and Adams County, Colorado, August 2009. Photo credit: Colorado Geological Survey

ON-010 Colorado Groundwater Atlas

Groundwater—as a critical natural resource for Colorado—is the focus of this informative and data-rich online publication from the CGS. Building on our previous award-winning Ground Water Atlas of Colorado, it features a wide range of easily accessible data from a variety of sources.

Martin Marietta Aggregates in Jefferson County, Colorado, March 2013. Photo credit: Michael O'Keeffe for the CGS.

ON-007-01 Colorado Aggregate Resources Map

This interactive map includes the digital versions of our sand, gravel, and quarry aggregate publications for most of the Front Range counties, Garfield County, and includes a statewide map of older quarry locations. Locations and resource ratings of these deposits are included to assist with land use planning and resource development in the Front Range and beyond.


Quick Links

Aerial mapping tools, Paonia Quadrangle, Colorado, August, 2013. Photo credit: Dave Noe for the CGS.

Map Portal

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SP-52 Messages in Stone cover


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MI-97 LiDAR-Based Map of the Cheraw Fault Scarp. Graphic credit: Colorado Geological Survey

GIS Data

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Looking northwest to Hells Kitchen from Ekkert, Colorado, towards Grand Mesa across the wide range of environments from

Colorado Geology

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Constellation Drive landslide, Colorado Springs, Colorado, August 2015. Photo credit: T.C.Wait for the CGS

Land Use Review

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ON-001 Colorado Earthquake and Fault Map


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Who we are and what we do …

About the CGS
Statewide map with POGI points.

Points of Geologic Interest

Given the spectacular geology that graces our state, we are happy to report that our new POGI map is now live! Check it out and let us know if you have any questions or additions!

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Rafting and kayaking through flood boulders in The Numbers Rapids, Upper Arkansas River, Colorado, August 2010. Photo credit: Keenan Lee.

Newest Miscellaneous Investigation (MI-) Series

MI-98 Catastrophic Glacial Outburst Floods on the Upper Arkansas River, Colorado

This publication from Mines Geology Professor Emeritus Keenan Lee is an in-depth exploration that illustrates one facet of the dramatic sweep of Colorado’s glacial past. With their high altitude, the central Rockies of Colorado saw numerous waves of intense glaciation, giving broad form to the mountains we see today. In particular, the Sawatch Range, with its Collegiate Peaks area to the west of the Upper Arkansas River valley was the site of glaciation several times in the last 700,000 years. Glacial terrains often feature dramatic ice- and land-forms. Lesser known are the occasional catastrophic events — also known as jökulhlaups — as are detailed in this report.

Check out some of our RockTalk blog postings ::

Case Study: geothermal gradient

The CGS has long been involved in researching the characteristics of geothermal energy across the state,…

HAZ-2021-01 Post-wildfire Hazards

Noting that we were getting hundreds of search hits on a previous version of an info-brochure that we originally published…

New GIS data and maps

For those of you who are subscribers to the CGS announcement list, we want to direct your attention to a…

Recent STATEMAP quadrangles

The CGS actively participates in the STATEMAP portion of…

Field Safety

It’s field mapping time, and much of our staff are out in several different areas of the state, doing field…

Case Study: The Trinidad, Colorado Earthquakes

[ED: Originally published in 2011 by Vincent Matthews, former State Geologist at the CGS.] Around midnight on August 22,…

OF-16-03 Colorado Rocky Mountain Front Profiles

(Ed: We’re reprising this blog post because we find that this poster is getting more and more popular with folks—for…

Trenching the Cheraw Fault in Southeastern Colorado

One of the missions of the CGS is to better understand the various geological risks that face the residents of…

Our most popular publications ::

Contact Us:

Colorado Geological Survey
Street and Mailing Address:
1801 Moly Road
Golden, Colorado  80401

telephone :: [+1] 303-384-2655

email ::

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