Photo credit: Chris Boyer, 2011

The Musselshell River communities have been working with the Montana Department of Natural Resources and Conservation (DNRC) and the Federal Emergency Management Agency (FEMA) 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.

New floodplain maps for Musselshell, Rosebud, and Petroleum Counties became effective 11/15/19.  Maps for Golden Valley go into effect 11/5/21.  Maps for Wheatland County are still going through public review. 

There can be insurance and development regulation implications for structures going into and coming out of the 100-Year Floodplain when new floodplain maps become effective.  Property owners can educate themselves and prepare for the adoption of the new floodplain maps by taking the steps below.

Are you Newly Mapped in a 100-Year Floodplain?  Click here for Cost-Saving Insurance Options

Wheatland and Golden Valley Counties

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

Preliminary Floodplain Map Viewer
Wheatland and Golden Valley Counties

Individual preliminary floodplain maps and studies can be viewed here: Preliminary Maps and Studies

Harlowton and Wheatland County - Appeal and Comment Period to start in late 2021

The City of Harlowton hosted an informational public meeting:
5:30-7pm Thursday, June 3
Harlowton Public Library - Conference Room, 13 Central Ave. S, Harlowton
Meeting materials:  100-Year Floodplain    Floodway (within 100-Year Floodplain)    500-Year Floodplain

A 90 Day Appeal and Comment Period is expected to be held for Wheatland County's preliminary maps and study, starting in late 2021.  

Golden Valley - New Maps and Study Effective November 5, 2021

No comments or appeals were received during the 90-Day Appeal and Comment Period for Golden Valley's preliminary maps and study (September 3 - December 2, 2020).  The maps and study will go into effect on November 5, 2021.  

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 Floodplain 

Mapping Status by County:

Know your Property's Flood Risk

When finalized, 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 Floodplain  

Appeal and Comment Periods

Before being finalized, floodplain maps and studies go through a lengthy technical and public review process, including a 90-Day Appeal and Comment Period.  Musselshell, Rosebud and Petroleum Counties completed their 90-Day Appeal and Comment period in January 2019.  The Appeal and Comment Period for Golden Valley County was held September 2 - December 3, 2020.  The Appeal and Comment Period for Wheatland County is anticipated to begin late 2021. Input on the preliminary maps and reports are encouraged and welcome.

Come back for more information

We will update this website with new, relevant information as the Musselshell River Flood Maps Update project moves forward. For more information about this project, contact Tiffany Lyden with Montana DNRC.