Mercer County, Illinois
The most common soil here is Muscatune, on about 10% of the land: a silt loam, smooth, like flour. Hickory and Osco come next.
About 57% of the land drains well, and 37% stays wet for long stretches; groundwater comes within two feet of the surface under 40% of it.
USDA rates 58% of the land very limited for a standard septic drain field, and 50% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 9% of the land floods occasionally or more, and bedrock lies within 40 inches under 2% of it.
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 Mercer 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 Mercer 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 |
|---|---|---|---|---|---|
| Muscatune silt loam, 0 to 2 percent slopes | 42K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Osco silt loam, 2 to 5 percent slopes | 23K | Well drained | B | Somewhat limited | Somewhat limited |
| Hickory silt loam, cool mesic, 18 to 35 percent slopes | 15K | Well drained | B | Very limited | Very limited |
| Orion silt loam, 0 to 2 percent slopes, frequently flooded | 14K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Rozetta silt loam, 2 to 5 percent slopes | 13K | Well drained | B | Somewhat limited | Somewhat limited |
| Fayette silt loam, glaciated, 5 to 10 percent slopes, eroded | 13K | Well drained | B | Somewhat limited | Somewhat limited |
| Hickory-Sylvan silt loams, 35 to 60 percent slopes | 10K | Well drained | B | Very limited | Very limited |
| Greenbush silt loam, 5 to 10 percent slopes, eroded | 10K | Well drained | B | Somewhat limited | Somewhat limited |
| Greenbush silt loam, 2 to 5 percent slopes | 10K | Well drained | B | Somewhat limited | Somewhat limited |
| Sylvan silty clay loam, 10 to 18 percent slopes, severely eroded | 10K | Well drained | B | Somewhat limited | Somewhat limited |
| Ipava silt loam, 0 to 2 percent slopes | 9K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Titus silty clay loam, 0 to 2 percent slopes, rarely flooded | 8K | Poorly drained | C/D | Very limited | Very limited |
| Elco-Atlas silty clay loams, 10 to 18 percent slopes, severely eroded | 7K | Moderately well drained | C | Somewhat limited | Very limited |
| Seaton silt loam, 2 to 5 percent slopes | 6K | Well drained | B | Not limited | Somewhat limited |
| Osco silt loam, 5 to 10 percent slopes, eroded | 6K | Well drained | B | Somewhat limited | Somewhat limited |
| Joy silt loam, 0 to 2 percent slopes | 6K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Water | 6K | Not rated | Not rated | ||
| Atterberry silt loam, 0 to 2 percent slopes | 6K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Radford silt loam, 0 to 2 percent slopes, frequently flooded | 6K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Sparta loamy sand, Illinois till plain, 2 to 6 percent slopes | 6K | Excessively drained | A | Not 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 50% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 58% 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
Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.