Marshall County, Oklahoma
Shrink-swell clay limits houses without basements on 30% of Marshall County's mapped land, a higher share than 80% of US counties. A shallow water table limits basements on 1%.
99.7% 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. 42% of homes were built before 1980, against 50% nationally; the median home dates from 1985.
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 Marshall County
| Expansive clay (limits slab homes) | 29.9% |
| High water table (limits basements) | 1.3% |
| Septic fields very limited | 60.0% |
| Clay swell (LEP, by area) | 7.4% |
| High-swell land (LEP 6%+) | 36.9% |
| Mapped soil | 273,465 acres |
| Soil series | Share here | Series nationally: expansive clay |
|---|---|---|
| Konsil | 21% | n/a |
| Ferris | 11% | n/a |
| Purves | 8% | 40% |
| Swink | 8% | n/a |
| Durant | 7% | n/a |
| Konawa | 7% | n/a |
How we count · survey areas OK095 (2025-08-29)
What the numbers mean here
Clay swell averages a linear extensibility of 7.4% by land area here, and 37% 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: 99.7% of the county is in drought on the latest map, and 30% of Marshall County's mapped land has shrink-swell clay.
Rain over the 12 months to August 2026: 33.48 in, 7.33 in below the 1991-2020 average year of 40.81 in.
USDA rates 60% of the land very limited for septic absorption fields.
Drought
99.7% of the county is in drought (D1 or worse) on the October 13, 2026 map. Part of the county was in drought in 49 of the last 52 weeks; the most was 100% of its area, in 27 weeks, most recently on the October 6, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 100% |
| D1 moderate drought or worse | 99.7% |
| D2 severe or worse | 85.5% |
| D3 extreme or worse | 0% |
| D4 exceptional | 0% |
Flood losses since 2016
FEMA's flood data list no flood losses in Marshall County since 2016.
Rain
| Average year, 1991-2020 | 40.81 in |
| 12 months to August 2026 | 33.48 in (-7.33) |
| 2025 | 44.63 in (+3.82) |
| Wettest year since 1895 | 2015: 75.95 in |
| Driest year since 1895 | 1963: 18.35 in |
| Days with 1 inch or more, normal at MADILL (4 mi away) | 13.7 |
Homes
| Housing units | 8,832 |
| Median year built | 1985 |
| Built before 1980 | 42% |
| Built 2000 or later | 27% |
| Owner-occupied | 78% |
| Median value, owner-occupied | $164,500 |
| Single-family detached | 60% |
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 |
|---|---|---|---|
| Johnston County, OK | 21 mi | 21% | 19% |
| Love County, OK | 28 mi | 17% | 2% |
| Grayson County, TX | 28 mi | 60% | 4% |
| Bryan County, OK | 29 mi | 42% | 19% |
| Carter County, OK | 33 mi | 23% | 3% |
| Murray County, OK | 36 mi | 29% | 7% |
| Cooke County, TX | 37 mi | 38% | under 1% |
| Coal County, OK | 47 mi | 54% | 71% |
Sources: USDA SSURGO (August 29, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status