Madison County, and the Towns of Ennis, Sheridan, and Twin Bridges have been working with the Federal Emergency Management Agency (FEMA) and Montana Department of Natural Resources and Conservation (DNRC) to produce new floodplain maps for portions of the Jefferson River, Beaverhead River, Ruby River, Madison River, South Boulder River, and Mill and Indian Creeks in Madison County.

View study extents here.

Updated floodplain maps will depict the latest, most accurate flood risk data, and will eventually result in updated FEMA floodplain maps. The existing FEMA and Madison County floodplain maps are based on data from the 1980s and 1990s.

New floodplain maps from this project are not expected to be finalized for a while – the study information and maps need to go through a lengthy technical and public review process.  When finalized, new maps could have effects on some property owners in mapped 100-year floodplains. See: 100 year Floodplain Fact Sheet.

View Draft Data

New floodplain studies involve collecting and analyzing data, including: topography, hydrology analyses and hydraulic analyses.  View available draft data here:

Jefferson River Watershed Draft Hydrologic Analysis

Madison River Watershed Draft Hydrologic Analysis

More draft data and information will be posted as it becomes available.

Come back for more information

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

Know your property's flood risk

Flood Insurance Rate Maps indicate areas of flood risk. Once this project is complete, updated Flood Insurance Rate Maps will provide more accurate, current, and detailed data and mapping of flood risk areas.

For questions or more information, email or call Tiffany Lyden, DNRC Floodplain Outreach Specialist (406-444-0599).