The Goosenecks on the Yampa River in Dinosaur National Monument, Colorado, April 2019. Photo credit: ©2019 hopkins/neoscenes, used by permission.

Colorado Geological Survey

When rocks talk, we listen!

The Colorado Geological Survey (CGS) is a non-regulatory 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.

Aggregate stock at the north end of the San Luis Valley, Colorado, May @2009 hopkins/neoscenes

ON-007-01 Colorado Aggregate Resources Map

Many naturally occurring aggregates, such as sand, gravel, and crushed stone are produced around the state. They are used in a wide variety of ways including construction fill, concrete, road base along with rip-rap, snow and ice control, filtration systems, railroad ballast, hydraulic fracturing, and roofing granules.


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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The Goosenecks on the Yampa River in Dinosaur National Monument, Colorado, April ©2018 hopkins/neoscenes

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
The K–Pg (Cretaceous-Paleogene) boundary exposure at Longs Canyon in Trinidad Lake State Park, Colorado, shows an abrupt change from dark- to light-colored rock, October ©2019 hopkins/neoscenes.

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 the >RockTalk< blog for the latest news on the CGS and Colorado geoscience ::

Contact Us:

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

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

email ::

  • Use this form to ask us … anything!