County · code 30065
Musselshell CountyMontana
Musselshell County is a county in Montana with a county seat in Roundup, formed in 1911.
- Founded1911
- County seatRoundup
- Named forMusselshell River, Montana
- Land area1,869 sq mi + 2.8 sq mi water
- Population4,730 2020 Census
- Parcels mapped8,052 checked 14 October 2026
Where it is
Musselshell on the map of Montana
Montana has 56 counties and county equivalents, each with its own records office. Shapes with a page are links.
History
Formed in 1911 from Fergus County, Meagher County and Yellowstone County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Musselshell County was created on March 1, 1911, from parts of Fergus, Meagher, and Yellowstone counties. The county was named after the Musselshell River. In 1917, Musselshell exchanged territory with Rosebud County, and in 1920, it lost land to the creation of Golden Valley County.
- 1911Musselshell County created Musselshell created from Fergus, Meagher, and Yellowstone. Act passed 11 February 1911; took effect 1 March 1911. · Mont. Laws 1911, 12th leg., ch. 25/pp. 29-38
- 1917Exchanged territory Musselshell exchanged with Rosebud. · Mont. Laws 1917, 15th leg., ch. 108/pp. 177-178
- 1920Lost territory Musselshell lost to creation of Golden Valley. · Mont. Rev. Code 1921, sec. 4323/pp. 1581-1582; Burlingame, 17-20
Land and parcels
What the maps cover in Musselshell
Who publishes each layer, how good it is, and when we last checked.
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Parcels Good enough
Lot lines and tax-map numbers for 8,052 parcels. Drawn for tax purposes: usually within a few feet of a survey, but not a survey.
checked 14 October 2026 -
Address points Official
One point per address, 2,959 in all from Montana State Library.
edited 13 October 2026 · checked 14 October 2026 -
Buildings Reference
Roof outlines traced from aerial imagery from FEMA Response Geospatial Office with Oak Ridge National Laboratory (ORNL). Good for seeing what is on a lot; not accurate enough to set a fence from.
checked 18 October 2026
- Official
- from the office that keeps the record
- Good enough
- a reliable statewide or national copy
- Fallback
- a guide only; check the official record
- Missing
- nothing public found yet
People and land
Musselshell by the Census
Source: US Census Bureau, 2020 Census; US Census Bureau, 2020 Gazetteer Files. Not endorsed or certified by the Census Bureau.
Rules and offices
Musselshell County's official site
We have found the county's site but not its offices yet; start there.
County government
- County government
The official website of Musselshell County.
See your own lot on these maps
Open Musselshell County on Parcel Chart's free map and click your parcel. Save it with a free account; the full record of your place (site map, projects, documents) is Pro, in early access.
Questions
Common questions about Musselshell County
- When was Musselshell County founded?
- Musselshell County was founded in 1911, formed from Fergus County, Meagher County and Yellowstone County, and named after Musselshell River, Montana.
- What is the county seat of Musselshell County?
- The county seat of Musselshell County is Roundup.
- Is there an online parcel map for Musselshell County?
- Yes. A public source publishes a parcel map of 8,052 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Musselshell County's boundary or name changed?
- Musselshell County was created in 1911 from Fergus County, Meagher County and Yellowstone County. Since then the Atlas of Historical County Boundaries records 2 later changes, chiefly involving Golden Valley County and Rosebud County.
- Is my lot in a flood zone?
- We do not have flood maps for Musselshell County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby