Soil series profile
McRae soil series
McRae is a well drained soil with a loam surface, mapped on 226,847 acres in 6 counties in MT. Hydrologic group B.
- Drainage class
- Well drained 100% of mapped acres
- Hydrologic group
- B 100% of mapped acres
- Typical topsoil pH
- 7.9 moderately alkaline · range 7.9–7.9
- Mapped area
- 227k acres in 6 counties, 1 state
Typical McRae profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–5 in (Ap) | Loam | 7.9 | 24% | 39% | 3% |
| 5–11 in (Bk) | Loam | 7.9 | 26% | 38% | 1.5% |
| 11–60 in (C) | Loam | 8.2 | 26% | 38% | 0.5% |
What this means
What McRae soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in McRae soils is moderately alkaline: pH 7.9. Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).
Loamy topsoil (loam, silt loam and similar) covers 100% of mapped McRae acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is loam (74% of mapped McRae acres).
100% of mapped McRae acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
Most land is in hydrologic groups B and C, where rain soaks in at a moderate pace.
For a septic system
For conventional septic absorption fields, NRCS rates 2% of the acres in mapped McRae soils very limited, 98% somewhat limited and 0% not limited.
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where McRae soil is found
Mapped acres
McRae is mapped in Montana.
| County | Acres | Share of county land |
|---|---|---|
| Yellowstone County, MT | 105,967 | 6.3% |
| Treasure County, MT | 31,918 | 5.1% |
| Powder River County, MT | 30,407 | 1.6% |
| Rosebud County, MT | 29,163 | 0.6% |
| Big Horn County, MT | 27,371 | 0.6% |
| Carbon County, MT | 2,021 | 0.2% |
Septic absorption fields
NRCS rating, share of McRae acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 97.6% |
| Very limited | 2.4% |
Drainage, water table and flooding
Share of McRae acres
- Depth to seasonal high water table
- None reported within about 6.5 feet (median where reported).
- Flooding
- Not mapped as flooding on most acres.
- Slope
- Typically 1–14% (median 6%).
- Topsoil organic matter
- Median 3%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 100.0% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% |
| B: moderate infiltration | 100.0% |
| C: slow infiltration | 0.0% |
| D: very slow infiltration (clayey, shallow or wet) | 0.0% |
| A/D: D as is, A if drained | 0.0% |
| B/D: D as is, B if drained | 0.0% |
| C/D: D as is, C if drained | 0.0% |
Sources & data dates
- Source
- USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
- Data date
- SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
- Scope
- All map unit components named McRae (component kind "Series") in SSURGO: 226,847 acres.
- Method
- Shares are by mapped acres of McRae components. The profile comes from the single largest McRae component. Full methodology.