Treasure County, Montana
The most common soil here is Midway, on about 18% of the land: a clay, sticky when wet and rock-hard when dry. Bainville and Havre come next.
About 95% of the land drains well, and 3% stays wet for long stretches.
USDA rates 85% of the land very limited for a standard septic drain field, and 72% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 4% of the land floods occasionally or more, and bedrock lies within 40 inches under 65% 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 Treasure 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 D (very slow infiltration, high runoff). The most common soil order is Entisols — young soils with little profile development, often on floodplains or steep slopes. 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 Treasure 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 |
|---|---|---|---|---|---|
| Midway-Bainville complex | 79K | Well drained | D | Very limited | Very limited |
| Midway clay loam, 15 to 35 percent slopes | 41K | Well drained | D | Very limited | Very limited |
| Midway-Shale outcrop complex, 4 to 35 percent slopes | 29K | Well drained | D | Very limited | Very limited |
| Midway-Nihill gravelly loam | 24K | Well drained | D | Very limited | Very limited |
| Pierre-Lismas clays, saline-Alkali | 24K | Well drained | D | Very limited | Very limited |
| Hoven and McKenzie soils | 20K | Well drained | D | Very limited | Very limited |
| McRae-Bainville loams, 8 to 20 percent slopes | 20K | Well drained | B | Somewhat limited | Somewhat limited |
| Bainville loam, 15 to 35 percent slopes | 18K | Well drained | D | Very limited | Very limited |
| Bainville-Midway complex, 15 to 35 percent slopes | 16K | Well drained | D | Very limited | Very limited |
| Bainville-Shale outcrop complex | 16K | Well drained | D | Very limited | Very limited |
| Havre loam | 13K | Well drained | B | Very limited | Somewhat limited |
| Pierre-Lismas clays | 12K | Well drained | D | Very limited | Very limited |
| Marias clays, fans, saline-alkali | 12K | Well drained | D | Very limited | Very limited |
| Marias-Hoven clays, saline | 12K | Well drained | D | Very limited | Very limited |
| Lismas-Pierre clays, saline-Alkali | 12K | Well drained | D | Very limited | Very limited |
| Lismas-Midway complex | 11K | Well drained | D | Very limited | Very limited |
| Bainville loam, 8 to 15 percent slopes | 11K | Well drained | C | Somewhat limited | Very limited |
| Blacksheep-Twilight fine sandy loams, 15 to 40 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Cushman loam, 4 to 8 percent slopes | 9K | Well drained | C | Somewhat limited | Very limited |
| Fort Collins loam, 4 to 8 percent slopes | 9K | Well drained | B | Not limited | Somewhat 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 72% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, 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.