Morgan County, Illinois
A shallow water table limits basements on 54% of Morgan County's mapped land, a higher share than 70% of US counties. Shrink-swell clay limits houses without basements on 43%.
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. 73% of homes were built before 1980, against 50% nationally; the median home dates from 1965.
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 Morgan County
| Expansive clay (limits slab homes) | 43.0% |
| High water table (limits basements) | 54.0% |
| Septic fields very limited | 64.1% |
| Clay swell (LEP, by area) | 4.8% |
| High-swell land (LEP 6%+) | 28.8% |
| Mapped soil | 367,180 acres |
How we count · survey areas IL137 (2025-08-31)
What the numbers mean here
Clay swell averages a linear extensibility of 4.8% by land area here, and 29% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 43% of the mapped land.
On 54% of Morgan County's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
Rain over the 12 months to August 2026: 36.26 in, 2.73 in below the 1991-2020 average year of 38.99 in.
USDA rates 64% 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 22 of the last 52 weeks; the most was 100% of its area, in 21 weeks, most recently on the March 10, 2026 map.
| Category, October 13, 2026 | Share of county |
|---|---|
| D0 abnormally dry or worse | 30.1% |
| 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, $250,017 paid. The worst year was 2019, with 3.
| Year | Flood losses |
|---|---|
| 2016 | 0 |
| 2017 | 0 |
| 2018 | 1 |
| 2019 | 3 |
| 2020 | 0 |
| 2021 | 1 |
| 2022 | 0 |
| 2023 | 0 |
| 2024 | 0 |
| 2025 | 0 |
| 2026 to date | 0 |
Rain
| Average year, 1991-2020 | 38.99 in |
| 12 months to August 2026 | 36.26 in (-2.73) |
| 2025 | 27.27 in (-11.72) |
| Wettest year since 1895 | 1993: 55.05 in |
| Driest year since 1895 | 1901: 23.67 in |
| Days with 1 inch or more, normal at JACKSONVILLE 2E (1 mi away) | 10.1 |
Homes
| Housing units | 15,016 |
| Median year built | 1965 |
| Built before 1980 | 73% |
| Built 2000 or later | 11% |
| Owner-occupied | 73% |
| Median value, owner-occupied | $130,800 |
| Single-family detached | 76% |
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 |
|---|---|---|---|
| Scott County, IL | 16 mi | 27% | 47% |
| Cass County, IL | 18 mi | 13% | 45% |
| Greene County, IL | 27 mi | 20% | 51% |
| Sangamon County, IL | 29 mi | 58% | 72% |
| Menard County, IL | 30 mi | 27% | 51% |
| Brown County, IL | 33 mi | 29% | 38% |
| Macoupin County, IL | 35 mi | 62% | 78% |
| Pike County, IL | 37 mi | 9% | 56% |
Sources: USDA SSURGO (August 31, 2025) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · NOAA (August 2026) · Census ACS 2020-2024. Methods · Data status