Garfield County, Montana
Shrink-swell clay limits houses without basements on 22% of Garfield County's mapped land, a higher share than 73% of US counties. A shallow water table limits basements on under 1%.
None of the county is in drought on the October 13, 2026 Drought Monitor map. FEMA's flood data list 5 flood losses here since 2016. 53% of homes were built before 1980, against 50% nationally; the median home dates from 1978.
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 Garfield County
| Expansive clay (limits slab homes) | 22.1% |
| High water table (limits basements) | 0.4% |
| Septic fields very limited | 65.6% |
| Clay swell (LEP, by area) | 4.2% |
| High-swell land (LEP 6%+) | 20.1% |
| Mapped soil | 2,987,628 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Cambeth | 10% | n/a |
| Cabbart | 9% | under 1% |
| Lonna | 8% | n/a |
| Yamacall | 4% | n/a |
| Twilight | 4% | n/a |
| Kobase | 4% | n/a |
How we count · survey areas MT033 (2025-08-28)
What the numbers mean here
Clay swell averages a linear extensibility of 4.2% by land area here, and 20% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 22% of the mapped land.
Rain over the 12 months to August 2026: 13.18 in, 0.98 in below the 1991-2020 average year of 14.16 in.
USDA rates 66% of the land very limited for septic absorption fields.
Drought
0% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 41 of the last 52 weeks; the most was 100% of its area, in 4 weeks, most recently on the June 23, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 0.1% |
| D1 moderate drought or worse | 0% |
| D2 severe or worse | 0% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
5 flood losses since 2016, $105,461 paid. The worst year was 2026, with 3.
| Year | Flood losses |
|---|---|
| 2016 | 1 |
| 2017 | 0 |
| 2018 | 0 |
| 2019 | 0 |
| 2020 | 0 |
| 2021 | 0 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 1 |
| 2026 to date | 3 |
Rain
| Average year, 1991-2020 | 14.16 in |
| 12 months to August 2026 | 13.18 in (-0.98) |
| 2025 | 15.21 in (+1.05) |
| Wettest year since 1895 | 1927: 21.50 in |
| Driest year since 1895 | 1960: 6.51 in |
| Days with 1 inch or more, normal at BRUSETT 3 N (20 mi away) | 2.9 |
Homes
| Housing units | 730 |
| Median year built | 1978 |
| Built before 1980 | 53% |
| Built 2000 or later | 27% |
| Owner-occupied | 72% |
| Median value, owner-occupied | $169,900 |
| Single-family detached | 75% |
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 |
|---|---|---|---|
| Petroleum County, MT | 58 mi | 57% | under 1% |
| McCone County, MT | 63 mi | 12% | under 1% |
| Treasure County, MT | 73 mi | 44% | 4% |
| Valley County, MT | 76 mi | 51% | 2% |
| Prairie County, MT | 77 mi | 10% | 1% |
| Rosebud County, MT | 77 mi | 25% | under 1% |
| Phillips County, MT | 81 mi | 64% | 2% |
| Musselshell County, MT | 86 mi | 24% | 1% |
Sources: USDA SSURGO (August 28, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status