Jefferson County Flood Maps Update

Jefferson County has been working with the Federal Emergency Management Agency (FEMA) and Montana Department of Natural Resources and Conservation (DNRC) to produce new and updated 100-year floodplain maps. The project includes updating all the existing mapped floodplains in the county, and producing new floodplain maps for portions of Prickly Pear Creek and tributaries in the northern part of the county.

Updated floodplain maps will depict the latest, most accurate flood risk data, and will eventually result in updated FEMA floodplain maps. Most of the existing FEMA floodplain maps in Jefferson County are based off of data from the 1970s. For more information see: Floodplain FAQs Flood Study Process

Project Timeline

Flood Insurance Rate Maps indicate areas of flood risk. Once this project is complete, new and updated Flood Insurance Rate Maps will provide more accurate, current, and detailed data and mapping of flood risk areas. New floodplain studies involve collecting and analyzing data, including: topography, hydrology analyses and hydraulic analysis.

UPDATE August 2025 We will update this website with new, relevant information as it is available.

Project Updates

The Formal 90 day appeal and comment period will begin September 10, 2025 and will run through December 9, 2025. To learn more about this formal process please review the documents below:

90 Day Appeal and Comment Period FEMA appeal information image

Appeals and Comments

The formal 90-day appeal and comment period is ran through the community offices. All submittals must include a completed appeal / comment form. Please contact your local floodplain administrator in Jefferson County, Boulder or Whitehall for more information.

Public Open House Meetings

View Preliminary Flood Insurance Rate Maps

The preliminary flood study information and maps need to go through a lengthy technical and public review process before being finalized. When finalized, new maps could have effects on some property owners in mapped floodplains.