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.
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.
ON-007-01 Colorado Aggregate Resources Map
This interactive map includes the digital versions of our sand, gravel, and quarry aggregate publications for Colorado’s populous counties. The map consists of locations and resource ratings of these deposits to assist with land use planning and resource development.ON-007-01
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.ON-010
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!Learn More
Case in point ::
Case Study: NARD
Natural Acid Rock Drainage
Are pristine mountain waters always clean and pure? Can streams unaffected by human activities and livestock influences be unfit for human consumption, or for aquatic life?
Case in point ::
Case Study: Lykins Formation
Karst morphology across the state
Small but significant areas of Colorado are underlain by bedrock that is composed of evaporative minerals. These are salts and sulfates that precipitate out of salt-concentrated surface waters.
Case in point ::
Case study: FHZ
Fluvial Hazard Zone
The Fluvial Hazard Zone (FHZ) is defined as the area a stream has occupied in recent history, may occupy, or may physically influence as it stores and transports water, sediment, and debris.
Latest Reports & Featured Topics
Newest annual survey of the state ::
IS-85 Colorado Mineral and Energy Industry Activities 2021-2022
Review of water and development plans and regulations ::
OF-20-09 Review of the Jefferson County Water Supply Policies and Analyses for Land Development in Mountain Areas
An ongoing issue in Colorado ::
HAZ-2021-01 Post-wildfire Hazards: Mud Slides :: Debris Flows
A look into Elbert County water ::
OF-18-12 Geology and Groundwater Resources of Elbert County, Colorado
Strategic minerals on an ancient seashore ::
RS-48 Beach Placer Mineral Deposits along Localized Paleoshorelines of the Western Interior Seaway, Upper Cretaceous Fox Hills Sandstone, Eastern Denver Basin, Colorado
Recent Statemap quadrangle map ::
OF-21-01 Geologic Map of the Barnesville Quadrangle, Weld County, Colorado
OF-22-09 Geochronology and Geomorphic Mapping to Estimate Debris-flow Depositional Ages and Recurrence Intervals Along State Highways 145 and 62, San Miguel County, Colorado
Working with the Colorado Department of Transportation (CDOT) to help understand potential geohazards threatening roads in San Miguel County, Colorado.
Our most popular publications :: (Please note that all physical publications for sale have been migrated to our Amazon storefront. All free digital downloads will continue to be available here.)
SP-43 A Guide to Swelling Soils for Colorado Homebuyers and Homeowners$9.00
SP-44 Geologic Excursions to the Rocky Mountain and Beyond, Field Trip Guidebook for the 1996 GSA Annual Meeting, Denver$0.00
SP-52 Messages in Stone: Colorado’s Colorful Geology (2nd Edition)$19.95
MI-66 Colorado Rockfall Simulation Program, Version 4.0$0.00
SP-57 Tourist Guide to Colorado Geology$12.00
IS-33 Gold Panning and Placering In Colorado: How and Where$12.00
MI-16 1979 Geologic Map of Colorado (Tweto)$0.00
MI-94 Colorado Geologic Time Scale Bookmark$0.00
MS-42 Colorado Springs Landslide Susceptibility Map, El Paso County, Colorado$0.00
MS-51 Interpretive Geothermal Gradient Map of Colorado$0.00
MS-45 Interpretive Geothermal Heat Flow Map of Colorado$0.00
RS-28 Gold Occurrences of Colorado$14.00