Big Horn County, Wyoming
USDA's soil survey flags shrink-swell clay on 12% of Big Horn County's mapped land and a shallow water table under basements on 4%, both below the national shares of 15% and 29%. The soil survey maps 85% of the county's land area; these shares describe the mapped part.
100% of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 1 flood losses here since 2016. 68% of homes were built before 1980, against 50% nationally; the median home dates from 1968.
Data as of October 13, 2026 · sources
expansive clay: shrink-swell limits slab homes
high water table: limits basements
in drought, October 13, 2026
of homes built before 1980
Soil under Big Horn County
| Expansive clay (limits slab homes) | 12.0% |
| High water table (limits basements) | 3.6% |
| Septic fields very limited | 66.5% |
| Clay swell (LEP, by area) | 3.7% |
| High-swell land (LEP 6%+) | 12.4% |
| Mapped soil | 1,706,745 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Persayo | 7% | n/a |
| Chipeta | 3% | n/a |
| Bributte | 3% | n/a |
| Worland | 3% | n/a |
| Greybull | 3% | n/a |
| Oceanet | 3% | n/a |
How we count · survey areas WY603 (2025-09-04), WY650 (2025-09-04)
What the numbers mean here
Rain over the 12 months to August 2026: 11.60 in, 1.77 in below the 1991-2020 average year of 13.37 in.
USDA rates 67% of the land very limited for septic absorption fields.
With shrink-swell clay on 12% and a shallow water table on 4% of the land, the soil survey points to neither problem across most of Big Horn County; conditions still vary lot by lot.
Drought
100% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 52 of the last 52 weeks; the most was 100% of its area, in 35 weeks, most recently on the October 13, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 100% |
| D2 severe or worse | 91.8% |
| D3 extreme or worse | 28.2% |
| D4 exceptional | 0% |
Flood losses since 2016
1 flood losses since 2016, $140,621 paid. The worst year was 2024, with 1.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 1 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 13.37 in |
| 12 months to August 2026 | 11.60 in (-1.77) |
| 2025 | 14.38 in (+1.01) |
| Wettest year since 1895 | 2011: 19.40 in |
| Driest year since 1895 | 1902: 7.27 in |
| Days with 1 inch or more, normal at BASIN (10 mi away) | 0.3 |
Homes
| Housing units | 5,372 |
| Median year built | 1968 |
| Built before 1980 | 68% |
| Built 2000 or later | 16% |
| Owner-occupied | 76% |
| Median value, owner-occupied | $216,500 |
| Single-family detached | 81% |
What repairs cost
Published ranges from cost guides, not quotes. More sources, and where they disagree.
Nearby counties
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Washakie County, WY | 47 mi | 5% | 2% |
| Sheridan County, WY | 58 mi | 21% | 1% |
| Hot Springs County, WY | 60 mi | 17% | 3% |
| Big Horn County, MT | 65 mi | 30% | 1% |
| Carbon County, MT | 70 mi | 30% | 2% |
| Johnson County, WY | 77 mi | 18% | 1% |
| Park County, WY | 79 mi | 12% | 9% |
| Yellowstone County, MT | 98 mi | 23% | 3% |
Sources: USDA SSURGO (September 4, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status