Soil series profile
Ethridge soil series
Ethridge is a well drained soil with a silty clay loam surface, mapped on 631,865 acres in 42 counties across 3 states. Hydrologic group C.
- Drainage class
- Well drained 100% of mapped acres
- Hydrologic group
- C >99% of mapped acres
- Typical topsoil pH
- 7.0 neutral · range 7.0–7.2
- Mapped area
- 632k acres in 42 counties, 3 states
Typical Ethridge profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–5 in (A) | Silty clay loam | 7.2 | 32% | 18% | 2% |
| 5–12 in (Bt) | Silty clay | 7.9 | 40% | 18% | 1.5% |
| 12–27 in (Bk) | Silty clay loam | 7.9 | 38% | 18% | 0.8% |
| 27–60 in (Bky) | Stratified silty clay loam to silt loam to loam | 7.9 | 32% | 18% | 0.3% |
What this means
What Ethridge soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Ethridge soils is neutral: pH 7.0 (most land between 7.0 and 7.2), the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Ethridge acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silty clay loam (63% of mapped Ethridge acres).
100% of mapped Ethridge acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 100% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.
For a septic system
For conventional septic absorption fields, NRCS rates 95% of the acres in mapped Ethridge soils very limited, 5% somewhat limited and 0% not limited.
Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Ethridge soil is found
Mapped acres
Ethridge is mapped in Montana, North Dakota and Wyoming.
| County | Acres | Share of county land |
|---|---|---|
| Chouteau County, MT | 85,409 | 3.4% |
| Garfield County, MT | 82,701 | 2.9% |
| Pondera County, MT | 55,231 | 5.2% |
| Phillips County, MT | 54,298 | 1.5% |
| Carter County, MT | 46,335 | 2.4% |
| Blaine County, MT | 33,857 | 1.2% |
| Liberty County, MT | 28,602 | 3.1% |
| Teton County, MT | 22,844 | 1.7% |
| Hill County, MT | 21,525 | 1.2% |
| Glacier County, MT | 20,895 | 1.3% |
| Toole County, MT | 19,800 | 1.8% |
| Sweet Grass County, MT | 18,880 | 1.5% |
| Petroleum County, MT | 18,737 | 1.8% |
| Valley County, MT | 15,952 | 0.5% |
| Cascade County, MT | 14,470 | 1.0% |
| Custer County, MT | 12,252 | 0.5% |
| Wheatland County, MT | 11,778 | 1.4% |
| Fallon County, MT | 9,780 | 0.9% |
| Fergus County, MT | 9,518 | 0.4% |
| Musselshell County, MT | 8,709 | 0.7% |
| McCone County, MT | 6,637 | 0.4% |
| Stillwater County, MT | 5,554 | 0.5% |
| Park County, MT | 5,351 | 0.3% |
| Golden Valley County, MT | 4,200 | 0.6% |
| Billings County, ND | 4,084 | 0.6% |
| Prairie County, MT | 2,498 | 0.2% |
| Carbon County, WY | 1,856 | 0.0% |
| Golden Valley County, ND | 1,769 | 0.3% |
| Slope County, ND | 1,612 | 0.2% |
| Bowman County, ND | 1,444 | 0.2% |
| McKenzie County, ND | 1,405 | 0.1% |
| Jefferson County, MT | 1,245 | 0.1% |
| Dawson County, MT | 1,113 | 0.1% |
| Meagher County, MT | 479 | 0.0% |
| Roosevelt County, MT | 338 | 0.0% |
| Silver Bow County, MT | 268 | 0.1% |
| Dunn County, ND | 215 | 0.0% |
| Madison County, MT | 147 | 0.0% |
| Treasure County, MT | 46 | 0.0% |
| Broadwater County, MT | 19 | 0.0% |
| Wibaux County, MT | 6 | 0.0% |
| Yellowstone County, MT | 5 | 0.0% |
Septic absorption fields
NRCS rating, share of Ethridge acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 4.6% |
| Very limited | 95.4% |
Drainage, water table and flooding
Share of Ethridge 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 1–5% (median 2%).
- Topsoil organic matter
- Median 2%.
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 | 0.0% |
| C: slow infiltration | 99.5% |
| D: very slow infiltration (clayey, shallow or wet) | 0.5% |
| 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 Ethridge (component kind "Series") in SSURGO: 631,865 acres.
- Method
- Shares are by mapped acres of Ethridge components. The profile comes from the single largest Ethridge component. Full methodology.