Fallon County, Montana

Survey Area MT025• Montana

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 Inceptisols — young soils with minimal horizon development but more than Entisols. 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 Fallon 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
Cabbart-Rock outcrop-Delpoint complex, 15 to 50 percent slopes	72K	Well drained	D	Very limited	Very limited
Cabbart-Cambeth silt loams, 8 to 15 percent slopes	57K	Well drained	D	Very limited	Very limited
Neldore clay, 4 to 15 percent slopes	36K	Well drained	D	Very limited	Very limited
Eapa loam, 2 to 8 percent slopes	35K	Well drained	B	Somewhat limited	Somewhat limited
Archin loam, 2 to 8 percent slopes	26K	Well drained	C	Not limited	Not limited
Kremlin loam, warm, 2 to 8 percent slopes	23K	Well drained	B	Not limited	Somewhat limited
Neldore-Bascovy clays, 4 to 15 percent slopes	22K	Well drained	D	Very limited	Very limited
Cambeth-Cabbart silt loams, 2 to 8 percent slopes	22K	Well drained	C	Somewhat limited	Very limited
Delpoint-Cabbart complex, 8 to 15 percent slopes	22K	Well drained	C	Somewhat limited	Very limited
Havre loam, 0 to 2 percent slopes	20K	Well drained	B	Very limited	Somewhat limited
Gerdrum clay loam, 2 to 8 percent slopes	20K	Well drained	D	Very limited	Not limited
Lonna silt loam, 2 to 8 percent slopes	19K	Well drained	C	Not limited	Very limited
Chinook sandy loam, 2 to 8 percent slopes	19K	Well drained	A	Not limited	Not limited
Gerdrum-Absher complex, 2 to 8 percent slopes	18K	Well drained	D	Very limited	Not limited
Blacksheep-Twilight fine sandy loams, complex, 8 to 15 percent slopes	17K	Well drained	D	Somewhat limited	Very limited
Archin-Absher complex, 2 to 8 percent slopes	16K	Well drained	D	Somewhat limited	Not limited
Lonna-Cabbart silt loams, 8 to 25 percent slopes	16K	Well drained	B	Somewhat limited	Somewhat limited
Busby-Twilight-Blacksheep fine sandy loams, 8 to 35 percent slopes	14K	Well drained	A	Very limited	Very limited
Cabbart silt loam, 4 to 15 percent slopes	14K	Well drained	D	Very limited	Very limited
Bonfri-Cabbart loams, 8 to 15 percent slopes	13K	Well drained	C	Somewhat 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.

Inceptisols

Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.

Mollisols

Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.

Entisols

Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.

Alfisols

Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.

What This Means

Building & Foundations

About 54% 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 61% 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.