County · code 30003
Big Horn CountyMontana
Big Horn County is a county in Montana with its county seat in Hardin. It was created on January 13, 1913.
- Founded1913
- County seatHardin
- Named forbighorn sheep
- Land area4,998 sq mi + 18 sq mi water
- Population13,124 2020 Census
- Parcels mapped14,987 checked 14 October 2026
Where it is
Big Horn 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 1913 from Rosebud County and Yellowstone County
An old deed may name a county that no longer exists, or a boundary that has since moved.
Big Horn County was created by petition and election from Rosebud County and Yellowstone County. The county was named after bighorn sheep.
- 1913Big Horn County created Big Horn created by petition and election from Rosebud and Yellowstone. · Mont. Rev. Code 1921, sec. 4306/pp. 1556-1557; Burlingame, 17-18
Land and parcels
What the maps cover in Big Horn
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 14,987 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, 6,309 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
Big Horn 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
Big Horn 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 Big Horn County.
See your own lot on these maps
Open Big Horn 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 Big Horn County
- When was Big Horn County founded?
- Big Horn County was founded in 1913, formed from Rosebud County and Yellowstone County, and named after bighorn sheep.
- What is the county seat of Big Horn County?
- The county seat of Big Horn County is Hardin.
- Is there an online parcel map for Big Horn County?
- Yes. A public source publishes a parcel map of 14,987 parcels, rated good enough here. You can click any parcel on it in Parcel Chart's free map, no sign-in needed.
- Has Big Horn County's boundary or name changed?
- Big Horn County was created in 1913 from Rosebud County and Yellowstone County. The Atlas of Historical County Boundaries records no boundary change since.
- Is my lot in a flood zone?
- We do not have flood maps for Big Horn County yet. Look up the address on FEMA's Flood Map Service Center, which shows the effective flood map for any lot.
Nearby