Horse Prairie-South Valley Area - Part of Beaverhead County, Montana
The most common soil here is Philipsburg, on about 5% of the land: a silt loam, smooth, like flour. Bronec and Maciver come next.
About 89% of the land drains well, and 7% stays wet for long stretches; groundwater comes within two feet of the surface under 6% of it.
USDA rates 80% of the land very limited for a standard septic drain field, and 62% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 1% of the land floods occasionally or more, and bedrock lies within 40 inches under 38% 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 Horse Prairie-South Valley Area - Part of Beaverhead County, Montana, 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 Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter. 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 Horse Prairie-South Valley Area - Part of Beaverhead County, Montana. 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 |
|---|---|---|---|---|---|
| Hardhart, very stony-Tropal-Rock outcrop complex, 15 to 50 percent slopes | 18K | Well drained | D | Very limited | Very limited |
| Dyce-Deepone-Dyce complex, 2 to 15 percent slopes | 17K | Well drained | D | Somewhat limited | Very limited |
| Maciver, very stony-Philipsburg-Tibson, very stony complex, 8 to 35 percent slopes | 17K | Well drained | C | Very limited | Very limited |
| Bronec, stony-Rockisland association, 15 to 50 percent slopes | 15K | Well drained | B | Very limited | Very limited |
| Tibson-Rockisland-Philipsburg association, 15 to 50 percent slopes | 14K | Well drained | B | Very limited | Very limited |
| Coyoteflats loam, 0 to 4 percent slopes | 13K | Well drained | B | Somewhat limited | Very limited |
| Water | 12K | Not rated | Not rated | ||
| Twinadams-Thunderhead-Blackleaf, stony complex, 15 to 35 percent slopes | 12K | Well drained | C | Very limited | Very limited |
| Trimad-Bronec complex, 4 to 15 percent slopes | 11K | Well drained | B | Not limited | Somewhat limited |
| Philipsburg gravelly loam, 2 to 15 percent slopes | 10K | Well drained | C | Somewhat limited | Very limited |
| Pensore, extremely stony-Crago, very stony-Rock outcrop complex, 8 to 50 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Cameahwait-Windlass complex, 0 to 4 percent slopes | 10K | Excessively drained | B | Somewhat limited | Very limited |
| Henneberry, very stony-Rock outcrop-Hardhart, very stony complex, 25 to 60 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Bronec-Conn complex, 2 to 15 percent slopes | 9K | Well drained | B | Not limited | Not limited |
| Philipsburg-Yacreek complex, 0 to 8 percent slopes | 9K | Well drained | B | Not limited | Somewhat limited |
| Varney-Coyoteflats complex, 2 to 8 percent slopes | 9K | Well drained | B | Somewhat limited | Somewhat limited |
| Philipsburg-Tibson, stony complex, 4 to 15 percent slopes | 9K | Well drained | C | Somewhat limited | Very limited |
| Libeg, very stony-Tiban, extremely stony-Houlihan complex, 20 to 60 percent slopes | 9K | Well drained | C | Very limited | Very limited |
| Donald-Philipsburg complex, 2 to 15 percent slopes | 8K | Well drained | C | Somewhat limited | Very limited |
| Bronec, very stony-Trimad, stony complex, 8 to 35 percent slopes | 8K | Well drained | B | 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 62% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes. A geotechnical assessment is recommended before building.
Septic Systems
About 80% 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.