Soil series profile
Delpoint soil series
Delpoint is a well drained soil with a loam surface, mapped on 1,285,964 acres in 48 counties across 2 states. Hydrologic group C.
- Drainage class
- Well drained 100% of mapped acres
- Hydrologic group
- C >99% of mapped acres
- Typical topsoil pH
- 7.5 slightly alkaline · range 7.4–8.0
- Mapped area
- 1.3M acres in 48 counties, 2 states
Typical Delpoint profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–3 in (A) | Loam | 8.0 | 24% | 39% | 2% |
| 3–12 in (Bw) | Loam | 8.2 | 27% | 38% | 0.75% |
| 12–28 in (Bk) | Loam | 8.5 | 27% | 38% | 0.25% |
| 28–60 in (Cr) | Bedrock | Not reported | Not reported | Not reported | Not reported |
What this means
What Delpoint soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Delpoint soils is slightly alkaline: pH 7.5 (most land between 7.4 and 8.0). 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 Delpoint acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is loam (96% of mapped Delpoint acres).
100% of mapped Delpoint acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On >99% 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 100% of the acres in mapped Delpoint soils very limited, 0% 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 Delpoint soil is found
Mapped acres
Delpoint is mapped in Montana and Wyoming.
| County | Acres | Share of county land |
|---|---|---|
| Rosebud County, MT | 186,858 | 3.8% |
| Big Horn County, MT | 161,630 | 3.6% |
| Musselshell County, MT | 131,104 | 11.2% |
| Garfield County, MT | 98,660 | 3.4% |
| Custer County, MT | 79,176 | 3.2% |
| Yellowstone County, MT | 66,910 | 4.0% |
| Teton County, MT | 56,484 | 4.2% |
| Fallon County, MT | 54,003 | 5.2% |
| Petroleum County, MT | 53,510 | 5.0% |
| Golden Valley County, MT | 52,797 | 7.2% |
| Carter County, MT | 50,929 | 2.7% |
| Prairie County, MT | 33,794 | 3.0% |
| Sweet Grass County, MT | 32,953 | 2.6% |
| Pondera County, MT | 27,779 | 2.6% |
| Fergus County, MT | 26,480 | 1.0% |
| Wheatland County, MT | 26,422 | 3.2% |
| Blaine County, MT | 16,488 | 0.6% |
| Carbon County, WY | 16,453 | 0.4% |
| Lincoln County, WY | 16,334 | 0.7% |
| Lewis and Clark County, MT | 15,349 | 0.7% |
| Valley County, MT | 12,837 | 0.4% |
| Meagher County, MT | 10,842 | 0.4% |
| Phillips County, MT | 9,411 | 0.3% |
| Campbell County, WY | 7,411 | 0.2% |
| Park County, WY | 7,231 | 0.4% |
| Chouteau County, MT | 7,079 | 0.3% |
| Hill County, MT | 6,410 | 0.3% |
| Liberty County, MT | 3,107 | 0.3% |
| Sweetwater County, WY | 2,403 | 0.0% |
| Cascade County, MT | 2,267 | 0.1% |
| Toole County, MT | 1,846 | 0.2% |
| McCone County, MT | 1,761 | 0.1% |
| Powder River County, MT | 1,731 | 0.1% |
| Hot Springs County, WY | 1,476 | 0.2% |
| Dawson County, MT | 1,255 | 0.1% |
| Beaverhead County, MT | 1,148 | 0.0% |
| Treasure County, MT | 1,045 | 0.2% |
| Stillwater County, MT | 1,029 | 0.1% |
| Park County, MT | 509 | 0.0% |
| Jefferson County, MT | 504 | 0.0% |
| Roosevelt County, MT | 182 | 0.0% |
| Crook County, WY | 144 | 0.0% |
| Glacier County, MT | 68 | 0.0% |
| Broadwater County, MT | 67 | 0.0% |
| Richland County, MT | 60 | 0.0% |
| Big Horn County, WY | 28 | 0.0% |
| Silver Bow County, MT | 1 | 0.0% |
| Madison County, MT | 0 | 0.0% |
Septic absorption fields
NRCS rating, share of Delpoint acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.0% |
| Very limited | 100.0% |
Drainage, water table and flooding
Share of Delpoint 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 5–35% (median 12%).
- 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 | 0.1% |
| C: slow infiltration | 99.9% |
| 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 Delpoint (component kind "Series") in SSURGO: 1,285,964 acres.
- Method
- Shares are by mapped acres of Delpoint components. The profile comes from the single largest Delpoint component. Full methodology.