Henry County, Illinois
The most common soil here is Osco, on about 12% of the land: a silt loam, smooth, like flour. Greenbush and Sylvan come next.
About 55% of the land drains well, and 41% stays wet for long stretches; groundwater comes within two feet of the surface under 42% of it.
USDA rates 61% of the land very limited for a standard septic drain field, and 45% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 12% of the land floods occasionally or more.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in Henry County, Illinois, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Well drained and the dominant hydrologic group is B (moderate infiltration). The most common soil order is Alfisols — moderately leached forest soils with a clay-enriched subsoil. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Henry County, Illinois. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Osco silt loam, 2 to 5 percent slopes | 42K | Well drained | B | Somewhat limited | Somewhat limited |
| Ipava silt loam, 0 to 2 percent slopes | 30K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Osco silt loam, 5 to 10 percent slopes, eroded | 25K | Well drained | B | Somewhat limited | Somewhat limited |
| Greenbush silt loam, 5 to 10 percent slopes, eroded | 23K | Well drained | B | Somewhat limited | Somewhat limited |
| Muscatune silt loam, 0 to 2 percent slopes | 20K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Radford silt loam, 0 to 2 percent slopes, frequently flooded | 19K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Sylvan silty clay loam, 10 to 18 percent slopes, severely eroded | 17K | Well drained | B | Somewhat limited | Somewhat limited |
| Greenbush silt loam, 2 to 5 percent slopes | 16K | Well drained | B | Somewhat limited | Somewhat limited |
| Elburn silt loam, 0 to 2 percent slopes | 15K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Sawmill silt loam, 0 to 2 percent slopes, frequently flooded, overwash | 14K | Poorly drained | B/D | Very limited | Very limited |
| Drummer silty clay loam, 0 to 2 percent slopes | 12K | Poorly drained | B/D | Very limited | Very limited |
| Fayette silt loam, glaciated, 5 to 10 percent slopes, eroded | 12K | Well drained | B | Somewhat limited | Somewhat limited |
| Plano silt loam, 2 to 5 percent slopes | 8K | Well drained | B | Somewhat limited | Very limited |
| Sawmill silty clay loam, 0 to 2 percent slopes, frequently flooded | 8K | Poorly drained | B/D | Very limited | Very limited |
| Harpster silty clay loam, 0 to 2 percent slopes | 7K | Poorly drained | B/D | Very limited | Very limited |
| Sylvan silt loam, 10 to 18 percent slopes, eroded | 7K | Well drained | B | Somewhat limited | Somewhat limited |
| Orion silt loam, 0 to 2 percent slopes, frequently flooded | 6K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Buckhart silt loam, 0 to 2 percent slopes | 6K | Moderately well drained | C | Somewhat limited | Very limited |
| Hickory clay loam, cool mesic, 10 to 18 percent slopes, severely eroded | 6K | Well drained | B | Somewhat limited | Somewhat limited |
| Ambraw loam, 0 to 2 percent slopes, occasionally flooded | 6K | Poorly drained | C/D | Very limited | Very limited |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 45% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 61% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Drainage is generally favorable for gardening. Adding compost and mulch will improve fertility and water retention. Test your soil's pH before planting — most vegetables prefer 6.0-7.0.