County Geologic Atlas Program

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County Geologic Atlas Program

Jan Falteisek, Supervisor, 651-259-5665



The program exists to develop maps and reports of the geology and hydrogeology of Minnesota. It is a joint program with the Minnesota Geological Survey (MGS).

Documents include maps and interpretations of geology, groundwater, pollution sensitivity, and special studies. Most projects provide GIS files of the geology and groundwater maps.

These documents are used by governments in long-range planning efforts to protect and preserve groundwater, provide information for permitting, for source water protection and well sealing programs, for short-term emergency response to contaminant releases, and by businesses and citizens.


County Geologic Atlases (CGAs) are studies of a county's geology and groundwater. Additional studies may include the distribution of sand and gravel deposits, sinkholes, or other features of interest.

  • Geologic studies (Part A) include both near-surface deposits and bedrock and are produced by the MGS.
  • Groundwater studies (Part B) include flow systems, aquifers, groundwater chemistry, and sensitivity to pollution and are produced by the DNR.

Regional Hydrogeologic Assessments (RGAs) are similar to CGAs but cover a larger area, typically four to nine counties in less detail. These older assessments will be replaced as new county atlases are completed.

Special Projects are topic-based studies commissioned to address specific issues.

Training is provided when an atlas is completed. Project staff instruct local staff and the public in how to use the maps and files at workshops through practical problem-solving exercises. 

User Assistance

Atlases brings you to downloadable files of maps, reports, and GIS data with selected chemistry and isotope data.

Contacts brings you to a list for specific questions on GIS, chemistry, and other projects.


Program funding comes from the DNR Ecological and Water Resources budget as appropriated by the legislature. Projects may also be supplemented by other funding sources that support geologic mapping at the MGS.

New atlas projects have been supported at the MGS since 2007 and the DNR since 2009 by additional funding from the Environment and Natural Resources Trust Fund as recommended by the Legislative-Citizen Commission on Minnesota Resources. Beginning in 2010, county geologic atlases have been supported by additional funding from the Clean Water Fund.

For a county atlas project, the state contributes from 80% to 85% of the project's total cost. The county supplements the state funding by contributing to the MGS an amount based on the individual county's ability to pay. It is also possible for a county to make arrangements to contribute local services in lieu of some, or all, of the cash payment