HomeOhioMercer CountySt. Henry
St. Henry, Ohio
Inside St. Henry's city limits, a shallow water table limits basements on over 99% of mapped land, the 2nd-highest of 9 cities in Mercer County. Shrink-swell clay limits houses without basements on 25%, the 4th-highest of 9 cities in Mercer County.
That water-table share is close to Mercer County's 95%. FEMA's flood data list no flood losses since 2016 in ZIP code 45883 overlapping the city. Of its 932 homes, 47% were built before 1980; the median dates from 1983.
Data as of October 13, 2026 · sources · in Mercer County
expansive clay: shrink-swell limits slab homes
high water table: limits basements
flood losses since 2016 in 1 overlapping ZIP
of homes built before 1980
Basement waterproofing in St. Henry
Basement waterproofing in St. Henry: a shallow water table limits basements on over 99% of St. Henry's mapped land, more than in 97% of Ohio cities.
About 800 of St. Henry's 932 homes are detached houses.
Soil under St. Henry city limits
| Expansive clay (limits slab homes) | 24.5% |
| High water table (limits basements) | 100.0% |
| Septic fields very limited | 100.0% |
| Clay swell (LEP, by area) | 4.7% |
| High-swell land (LEP 6%+) | 1.8% |
| Mapped soil | 1,137 acres |
What the numbers mean here
Clay swell averages a linear extensibility of 4.7% by land area here, and 2% of the land reaches USDA's high class (6% or more). Clay like that swells when wet and shrinks when dry, under 25% of the mapped land.
On over 99% of St. Henry's mapped land, soil stays saturated within about 6 feet of the surface for part of the year, which is basement depth.
USDA rates over 99% of the land very limited for septic absorption fields.
Drought in Mercer County
0% of Mercer County is in drought (D1 or worse) on the October 13, 2026 map. County detail.
Flood losses by ZIP code
FEMA flood records since 2016 in the ZIP codes that overlap St. Henry. ZIP areas reach past city limits.
| ZIP | Share of city land | Flood losses | Paid |
|---|---|---|---|
| 45883 | 100% | 0 | $0 |
Homes in St. Henry
| Housing units | 932 |
| Median year built | 1983 |
| Built before 1980 | 47% |
| Built 2000 or later | 27% |
| Owner-occupied | 87% |
| Median value, owner-occupied | $287,000 |
| Single-family detached | 84% |
Nearby cities
| Place | Distance | Expansive clay | High water table |
|---|---|---|---|
| Coldwater | 4 mi | 29% | over 99% |
| Burkettsville | 5 mi | 47% | over 99% |
| New Weston | 6 mi | 15% | 100% |
| Montezuma | 6 mi | 24% | 92% |
| Chickasaw | 7 mi | 19% | 93% |
| North Star | 7 mi | 28% | 100% |
| Fort Recovery | 8 mi | 16% | 95% |
| Osgood | 9 mi | 34% | 100% |
Sources: USDA SSURGO (August 5, 2026) · US Drought Monitor (October 13, 2026) · FEMA NFIP v3 (September 9, 2026) · Census ACS 2020-2024. Methods · Data status