Soil survey area

Prairie County, Montana

Survey Area MT079• Montana
The short version

The most common soil here is Lonna, on about 20% of the land: a silt loam, smooth, like flour. Cambeth and Cabbart come next.

About 93% of the land drains well.

USDA rates 82% of the land very limited for a standard septic drain field, and 41% very limited for homes with basements. That means extra cost or special design, not that it can't be done.

Worth knowing: 3% of the land floods occasionally or more, and bedrock lies within 40 inches under 59% 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 ground underfoot

The soils you're most likely standing on

The biggest named soils in Prairie County, Montana, each drawn five feet deep from its official USDA description, in its recorded colors.

Lonna
20% of the area
Silt loam topsoil · well drained
Smooth, like flour. Fertile and holds water well.
Inceptisols
Cambeth
11% of the area
Silt loam topsoil · well drained
Smooth, like flour. Fertile and holds water well.
Inceptisols
Cabbart
9% of the area
Loam topsoil · well drained
A balanced mix that crumbles in your hand. The gardener's ideal.
Entisols
Yamacall
3% of the area
Loam topsoil · well drained
A balanced mix that crumbles in your hand. The gardener's ideal.
Inceptisols
Floweree
3% of the area
Silt loam topsoil · well drained
Smooth, like flour. Fertile and holds water well.
Mollisols
Degrand
3% of the area
Loam topsoil · well drained
A balanced mix that crumbles in your hand. The gardener's ideal.
Mollisols

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 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 Prairie County, Montana. Search your address to find the exact soil composition, drainage, and series details at your specific location.

Soil Map UnitAcresDrainageHydro GroupDwellingsSeptic
Lonna-Cambeth-Cabbart silt loams, 4 to 12 percent slopes 123K Well drainedBSomewhat limitedVery limited
Lonna-Cambeth-Cabbart silt loams, 12 to 25 percent slopes 110K Well drainedCVery limitedVery limited
Lonna-Cambeth silt loams, 2 to 8 percent slopes 67K Well drainedCNot limitedVery limited
Lonna silt loam, 2 to 8 percent slopes 58K Well drainedCNot limitedVery limited
Cabbart-Rock outcrop-Yawdim complex, warm, 15 to 70 percent slopes 49K Well drainedDVery limitedVery limited
Badland 32K Not ratedNot rated
Degrand loam, 0 to 4 percent slopes 28K Well drainedBNot limitedSomewhat limited
Neldore-Rock outcrop-Abor complex, 15 to 50 percent slopes 27K Well drainedDVery limitedVery limited
Cambeth, calcareous-Cabbart-Yawdim complex, 4 to 25 percent slopes 24K Well drainedDVery limitedVery limited
Cambeth, calcareous-Cabbart-Lonna silt loams, 15 to 35 percent slopes 20K Well drainedCVery limitedVery limited
Lonna silt loam, 0 to 2 percent slopes 19K Well drainedCNot limitedVery limited
Yamacall-Busby-Blacksheep complex, 8 to 25 percent slopes 18K Well drainedBSomewhat limitedVery limited
Lihill-Yetull complex, 8 to 35 percent slopes 17K Somewhat excessively drainedAVery limitedVery limited
Cambeth, calcareous-Cabbart-Kirby complex, 8 to 45 percent slopes 16K Well drainedDVery limitedVery limited
Borollic Camborthids-Ustic Torrifluvents, complex, 0 to 8 percent slopes 15K Not ratedNot rated
Delpoint-Yamacall-Cabbart loams, 8 to 25 percent slopes 15K Well drainedCVery limitedVery limited
Floweree silt loam, calcareous, 2 to 8 percent slopes 15K Well drainedCSomewhat limitedVery limited
Delpoint-Cabbart-Yawdim complex, 25 to 70 percent slopes 14K Well drainedDVery limitedVery limited
Kremlin loam, warm, 2 to 8 percent slopes 13K Well drainedBNot limitedSomewhat limited
Cabbart-Cambeth-Rock outcrop, soft complex, 8 to 70 percent slopes 13K Well drainedDVery limitedVery 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 41% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.

Septic Systems

About 82% 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.

Look Up a Specific Address

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