Fergus County, Montana

Survey Area MT027• 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 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 Fergus 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
Thebo clay, 8 to 25 percent slopes	143K	Well drained	D	Very limited	Very limited
Dilts-Julin-Rock outcrop complex, 15 to 50 percent slopes	103K	Well drained	D	Very limited	Very limited
Neldore-Rock outcrop complex, 15 to 60 percent slopes	87K	Well drained	D	Very limited	Very limited
Neldore-Bascovy clays, 25 to 60 percent slopes	79K	Well drained	D	Very limited	Very limited
Winifred-Windham-Eltsac complex, 15 to 45 percent slopes	54K	Well drained	D	Very limited	Very limited
Yawdim-Delpoint-Rock outcrop complex, 25 to 50 percent slopes	52K	Well drained	D	Very limited	Very limited
Dilts-Thebo-Neldore clays, 4 to 60 percent slopes	50K	Well drained	D	Very limited	Very limited
Thebo clay, 2 to 8 percent slopes	50K	Well drained	D	Very limited	Very limited
Thebo-Weingart-Absher clays, 4 to 15 percent slopes	46K	Well drained	D	Very limited	Very limited
Doney-Wayden complex, 15 to 60 percent slopes	39K	Well drained	D	Very limited	Very limited
Yawdim-Abor-Rentsac complex, 8 to 60 percent slopes	39K	Well drained	D	Very limited	Very limited
Neldore-Bascovy clays, 4 to 25 percent slopes	38K	Well drained	D	Very limited	Very limited
Norbert-Eltsac clays, 15 to 60 percent slopes	38K	Well drained	D	Very limited	Very limited
Timberg-Castner complex, 15 to 45 percent slopes	38K	Well drained	D	Very limited	Very limited
Yamac-Delpoint-Yawdim complex, 4 to 25 percent slopes	36K	Well drained	D	Very limited	Very limited
Havre and Harlem soils, occasionally flooded	33K	Well drained	B	Very limited	Very limited
Rock outcrop	32K		D	Not rated	Not rated
Doney-Windham complex, 15 to 45 percent slopes	30K	Well drained	C	Very limited	Very limited
Eltsac-Norbert clays, 8 to 25 percent slopes	29K	Well drained	D	Very limited	Very limited
Fluvaquentic Haplaquolls, nearly level	28K			Not rated	Not rated

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.

Mollisols

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

Inceptisols

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

Alfisols

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

Vertisols

High-clay soils that shrink and swell dramatically. Fertile but challenging for foundations and septic systems.

Entisols

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

Aridisols

Dry-climate soils with low organic matter. Often have caliche layers that make excavation difficult. Low shrink-swell is good for foundations.

What This Means

Building & Foundations

About 94% 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 94% 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.