Yellowstone National Park, Wyoming-Montana-Idaho
The most common soil here is Como, on about 9% of the land: a very gravelly sandy loam, gritty and crumbly. Midfork and Kegsprings come next.
About 85% of the land drains well, and 3% stays wet for long stretches; groundwater comes within two feet of the surface under 16% of it.
USDA rates 87% of the land very limited for a standard septic drain field, and 44% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: bedrock lies within 40 inches under 42% 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 Yellowstone National Park, Wyoming-Montana-Idaho, 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 B (moderate infiltration). 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 Yellowstone National Park, Wyoming-Montana-Idaho. 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 |
|---|---|---|---|---|---|
| Hanks family-Como, family, moderately deep-Typic Cryorthents, shallow, complex | 170K | Well drained | A | Not limited | Very limited |
| Midfork-Arrowpeak families-Rock outcrop, complex | 115K | Well drained | B | Very limited | Very limited |
| Leighcan-Kangas families-Typic Cryaquepts, complex | 103K | Well drained | B | Not limited | Very limited |
| Water | 97K | Not rated | Not rated | ||
| Como-Como, moderately deep-McCort families, complex | 95K | Excessively drained | B | Not limited | Very limited |
| Bottle-Granturk-Windyridge families, complex | 94K | Somewhat excessively drained | D | Very limited | Very limited |
| Midfork-Storm families-Rock outcrop, complex | 91K | Well drained | B | Very limited | Very limited |
| Arrowpeak-Hobacker families-Rock outcrop, complex | 65K | Well drained | D | Very limited | Very limited |
| Rock outcrop-Rubble land-Piegan family, complex | 63K | D | Not rated | Not rated | |
| Tolby-Bottle families-Rock outcrop, complex | 62K | Somewhat excessively drained | B | Somewhat limited | Very limited |
| Kegsprings family-Rock outcrop-Matcher family, complex | 61K | Well drained | B | Very limited | Very limited |
| Midfork-Storm-Quazar families, complex | 56K | Well drained | B | Very limited | Very limited |
| Tolby-Sig families-Rock outcrop, complex | 50K | Excessively drained | D | Somewhat limited | Very limited |
| Kegsprings-Targhee families-Rock outcrop, complex | 49K | Well drained | B | Very limited | Very limited |
| Como-Waterpeak-Moran families, complex | 46K | Excessively drained | A | Not limited | Very limited |
| Gallatin, family, Typic Cryaquolls and Grayslake family, soils | 45K | Very poorly drained | C | Very limited | Very limited |
| Kegsprings family-Rock outcrop-Targhee family, complex | 39K | Well drained | B | Somewhat limited | Very limited |
| Rock outcrop-Rubble land-Arrowpeak family, complex | 37K | D | Not rated | Not rated | |
| Hobacker-Kegsprings families-Typic Cryaquolls, complex | 34K | Well drained | A | Very limited | Very limited |
| Como-Ledgefork families-Typic Cryaquepts, complex | 31K | Excessively drained | B | 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.
What This Means
Building & Foundations
About 44% 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.