Monroe County, Illinois
The most common soil here is Menfro, on about 17% of the land: a silt loam, smooth, like flour. Bunkum and Homen come next.
About 36% of the land drains well, and 47% stays wet for long stretches; groundwater comes within two feet of the surface under 49% of it.
USDA rates 85% of the land very limited for a standard septic drain field, and 75% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 34% 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 Monroe 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 C/D (varies with drainage). 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 Monroe 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 |
|---|---|---|---|---|---|
| Bunkum silty clay loam, 5 to 10 percent slopes, severely eroded | 13K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Homen silt loam, 2 to 5 percent slopes | 12K | Moderately well drained | C | Somewhat limited | Very limited |
| Fults silty clay, 0 to 2 percent slopes, occasionally flooded | 12K | Poorly drained | D | Very limited | Very limited |
| Bunkum silty clay loam, 10 to 18 percent slopes, severely eroded | 11K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Marine silt loam, 2 to 5 percent slopes | 9K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Menfro silt loam, karst, 25 to 60 percent slopes | 9K | Well drained | B | Very limited | Very limited |
| Ambraw silty clay loam, 0 to 2 percent slopes, occasionally flooded | 9K | Poorly drained | C/D | Very limited | Very limited |
| Menfro silt loam, karst, 12 to 25 percent slopes, severely eroded | 9K | Well drained | B | Very limited | Very limited |
| Landes very fine sandy loam, 2 to 5 percent slopes, occasionally flooded | 8K | Well drained | A | Very limited | Very limited |
| Stookey silt loam, 35 to 70 percent slopes | 8K | Well drained | B | Very limited | Very limited |
| Shaffton clay loam, 0 to 2 percent slopes, occasionally flooded | 8K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Wakeland silt loam, 0 to 2 percent slopes, frequently flooded | 7K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Water | 7K | Not rated | Not rated | ||
| Hickory silt loam, 18 to 35 percent slopes, eroded | 7K | Well drained | B | Very limited | Very limited |
| Booker clay, 0 to 2 percent slopes, occasionally flooded, long duration | 6K | Very poorly drained | D | Very limited | Very limited |
| Menfro silt loam, karst, 5 to 12 percent slopes, severely eroded | 6K | Well drained | B | Somewhat limited | Somewhat limited |
| Menfro silt loam, 2 to 5 percent slopes | 5K | Well drained | C | Somewhat limited | Somewhat limited |
| Homen silt loam, 5 to 10 percent slopes, eroded | 5K | Moderately well drained | C | Somewhat limited | Very limited |
| Atlas silty clay loam, 10 to 18 percent slopes, severely eroded | 5K | Somewhat poorly drained | D | Very limited | Very limited |
| Sonsac flaggy silt loam, 18 to 35 percent slopes | 5K | Well drained | 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 75% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 85% 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.