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Powder River County, Montana
Shrink-swell clay limits houses without basements on 30% of Powder River County's mapped land, a higher share than 80% of US counties. A shallow water table limits basements on under 1%.
The soil survey maps 90% 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 no flood losses here since 2016. 59% of homes were built before 1980, against 50% nationally; the median home dates from 1976.
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 Powder River County
| Expansive clay (limits slab homes) | 29.6% |
| High water table (limits basements) | 0.3% |
| Septic fields very limited | 80.4% |
| Clay swell (LEP, by area) | 4.9% |
| High-swell land (LEP 6%+) | 35.0% |
| Mapped soil | 1,893,431 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Midway | 19% | n/a |
| Cabba | 12% | n/a |
| Bainville | 9% | n/a |
| Ringling | 8% | n/a |
| Hesper | 5% | n/a |
| Haverson | 4% | n/a |
How we count · survey areas MT643 (2025-09-03)
What the numbers mean here
Clay swell averages a linear extensibility of 4.9% by land area here, and 35% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 30% of the mapped land.
Clay shrinks as it dries: 100% of the county is in drought on the latest map, and 30% of Powder River County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 12.78 in, 2.78 in below the 1991-2020 average year of 15.56 in.
USDA rates 80% of the land very limited for septic absorption fields.
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 35 of the last 52 weeks; the most was 100% of its area, in 22 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 | 96.7% |
| D3 extreme or worse | 84.1% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Powder River County since 2016.
Rain
| Average year, 1991-2020 | 15.56 in |
| 12 months to August 2026 | 12.78 in (-2.78) |
| 2025 | 18.37 in (+2.81) |
| Wettest year since 1895 | 2019: 22.64 in |
| Driest year since 1895 | 1936: 7.82 in |
| Days with 1 inch or more, normal at BROADUS (8 mi away) | 2.1 |
Homes
| Housing units | 972 |
| Median year built | 1976 |
| Built before 1980 | 59% |
| Built 2000 or later | 18% |
| Owner-occupied | 79% |
| Median value, owner-occupied | $192,100 |
| Single-family detached | 78% |
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 |
|---|---|---|---|
| Carter County, MT | 51 mi | 52% | 1% |
| Custer County, MT | 60 mi | 19% | 1% |
| Crook County, WY | 74 mi | 46% | under 1% |
| Rosebud County, MT | 75 mi | 25% | under 1% |
| Sheridan County, WY | 78 mi | 21% | 1% |
| Fallon County, MT | 84 mi | 21% | 1% |
| Campbell County, WY | 84 mi | 22% | 1% |
| Big Horn County, MT | 95 mi | 30% | 1% |
Sources: USDA SSURGO (September 3, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status