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DNRC Headquarters
1539 Eleventh Ave. Helena, MT 59601
Phone: (406) 444-2074 | Fax: (406) 444-2684
Questions? Email us

Musselshell River Flood Maps Update

Musselshell Flooding
Photo credit: Chris Boyer, 2011

The Musselshell River communities are currently working with the Federal Emergency Management Agency (FEMA) and the Montana Department of Natural Resources and Conservation (DNRC) to update floodplain maps for the Musselshell River and some of its tributary streams. Many of the existing floodplain maps are based on data from the 1970's. New floodplain maps will depict the latest, most accurate flood risk data, allowing property owners and communities to better understand their flood risk and to protect themselves against flooding.

There will be insurance and development regulation implications for structures going into and coming out of the 100-Year Floodplain when the maps become effective (July 13, 2017 for the Roundup Area and expected early 2019 for the rest of the Musselshell communities). Property owners should educate themselves and prepare for the adoption of the new floodplain maps by taking the steps below.

Public Meetings

Wheatland County, Harlowton, and Montana DNRC hosted two public open houses in Harlowton on 10/25/17. View the meeting materials:   Presentation  100-Year Floodplain   Floodway   500-Year Floodplain

Golden Valley County, Ryegate, Lavina, and Montana DNRC hosted two public open houses on 9/12/17.  View the meeting materials:   Presentation   100-Year Floodplain   Floodway    500-Year Floodplain

Musselshell, Rosebud, and Petroleum Counties and the City of Roundup hosted several public open houses last fall and winter. 

We will be scheduling additional public open houses -- stay tuned for updates. If you are unable to attend a meeting and/or need more information about this project, contact with Montana DNRC.

Know your Property's Flood Risk

Click the floodplain map viewer box below to view proposed map changes:

Preliminary Floodplain Map Viewer

Individual preliminary floodplain maps can be viewed here:
Preliminary Maps.

When finalized, the new maps could have effects on some property owners in mapped floodplains. If you are currently or will be mapped into a 100-Year Floodplain, view these links about your flood risk areas:  100-Year Floodplain   Floodway (within 100-Year Floodplain)    500-Year Floodplai

Roundup Area

FEMA map revisions for The Roundup Area have been through review and were issued on July 13, 2017.    

Click City of Roundup Map Revisions to view the City map. To view the full Roundup Letter of Map Revision click here.

Click Musselshell County Map Revisions to view the County map. To view the full Musselshell County Letter of Map Revision click here.

Check out these fact sheets for more information about what it means to live in a flood zone:
Roundup: 100-Year Floodplain
Roundup: Floodway (Within 100-Year Floodplain) 
Roundup: 500-Year Floodplain

Get technical information

 Check out our page with Preliminary Maps and technical data/reports.

Come back for more information

We will update this website with new, relevant information as the Musselshell River Flood Maps Update project moves forward.


More Info

Draft Maps & Technical Data
Musselshell Watershed Coalition 

Contact Info

Page Dringman
Golden Valley, Wheatland County, Ryegate
(406) 932-5470

Tiffany Lyden
Montana DNRC
(406) 444-0599