Dawson County, Montana
The most common soil here is Lonna, on about 21% of the land: a silt loam, smooth, like flour. Lambert and Cambeth come next.
About 95% of the land drains well.
USDA rates 87% of the land very limited for a standard septic drain field, and 43% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 7% of the land floods occasionally or more, and bedrock lies within 40 inches under 55% 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 Dawson 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 C (slow infiltration, moderate runoff). 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 Dawson 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 |
|---|---|---|---|---|---|
| Lonna-Cambeth silt loams, 2 to 8 percent slopes | 221K | Well drained | C | Not limited | Very limited |
| Lonna-Cambeth-Cabbart silt loams, 4 to 12 percent slopes | 120K | Well drained | B | Somewhat limited | Very limited |
| Lambert-Dimyaw complex, 15 to 65 percent slopes | 107K | Well drained | D | Very limited | Very limited |
| Lambert-Rock outcrop, soft complex, 15 to 70 percent slopes | 103K | Well drained | D | Very limited | Very limited |
| Lonna silt loam, 2 to 4 percent slopes | 76K | Well drained | C | Somewhat limited | Very limited |
| Tinsley-Lambert complex, 15 to 65 percent slopes | 75K | Excessively drained | A | Very limited | Very limited |
| Lonna, Havre, and Glendive soils, 0 to 4 percent slopes, occasionally flooded | 64K | Well drained | B | Very limited | Very limited |
| Badland | 54K | Not rated | Not rated | ||
| Lonna silt loam, 0 to 2 percent slopes | 38K | Well drained | C | Not limited | Very limited |
| Lambert gravelly loam, 20 to 40 percent slopes | 38K | Well drained | D | Very limited | Very limited |
| Lonna silt loam, 4 to 8 percent slopes | 34K | Well drained | C | Somewhat limited | Very limited |
| Lonna-Lambert complex, 4 to 25 percent slopes | 30K | Well drained | C | Somewhat limited | Very limited |
| Benz-Glendive complex, 2 to 15 percent slopes | 29K | Well drained | C | Very limited | Very limited |
| Subwell-Peerless loams, 0 to 4 percent slopes | 28K | Well drained | B | Not limited | Very limited |
| Lambert-Kirby complex, 15 to 65 percent slopes | 27K | Well drained | D | Very limited | Very limited |
| Vida-Zahill loams, 2 to 8 percent slopes | 25K | Well drained | C | Not limited | Very limited |
| Kremlin loam, warm, 2 to 8 percent slopes | 25K | Well drained | B | Not limited | Somewhat limited |
| Zahill-Lambert complex, 15 to 65 percent slopes | 22K | Well drained | C | Very limited | Very limited |
| Twilight-Yetull complex, 8 to 25 percent slopes | 19K | Well drained | B | Very limited | Very limited |
| Lambert-Yetull complex, 15 to 65 percent slopes | 18K | 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 43% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 87% 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.