Soil series profile
Clarksville soil series
Clarksville is a somewhat excessively drained soil with a extremely gravelly silt loam surface, mapped on 2,802,758 acres in 84 counties across 8 states. Hydrologic group B.
- Drainage class
- Somewhat excessively drained 95% of mapped acres
- Hydrologic group
- B 68% of mapped acres
- Typical topsoil pH
- 4.5 very strongly acidic · range 4.4–5.3
- Mapped area
- 2.8M acres in 84 counties, 8 states
Typical Clarksville profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–24 in (A) | Extremely gravelly silt loam | 5.3 | 17% | 29% | 1.75% |
| 24–72 in (Bt) | Extremely gravelly silt loam | 5.0 | 27% | 17% | 0.25% |
What this means
What Clarksville soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Clarksville soils is very strongly acidic: pH 4.5 (most land between 4.4 and 5.3). Most vegetables and lawn grasses do best around 6.0 to 7.0, so lime is often needed; blueberries, azaleas and rhododendrons like it as it is.
Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Clarksville acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is very gravelly silt loam (70% of mapped Clarksville acres).
>99% of mapped Clarksville acres is excessively or somewhat excessively drained: water moves through fast, so gardens need more frequent watering in dry spells.
For lawns and yards
27% of mapped acres is in hydrologic group A, where water soaks in fast. Lawns there dry out quickly; deeper, less frequent watering and organic matter help.
For a septic system
For conventional septic absorption fields, NRCS rates 84% of the acres in mapped Clarksville soils very limited, 16% 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 Clarksville soil is found
Mapped acres
Clarksville is mapped in Missouri, Oklahoma, Arkansas, Tennessee, Alabama, Illinois, Kentucky and Kansas. The 60 counties with the most Clarksville acres:
| County | Acres | Share of county land |
|---|---|---|
| Delaware County, OK | 183,157 | 38.9% |
| Cherokee County, OK | 138,190 | 28.8% |
| Benton County, AR | 135,580 | 25.2% |
| Dent County, MO | 132,220 | 27.4% |
| Adair County, OK | 131,536 | 35.8% |
| Wright County, MO | 105,655 | 24.2% |
| Carter County, MO | 105,640 | 32.6% |
| Wayne County, MO | 92,494 | 19.1% |
| Reynolds County, MO | 87,760 | 17.0% |
| Shannon County, MO | 82,068 | 12.8% |
| Laclede County, MO | 81,011 | 16.5% |
| Pulaski County, MO | 73,818 | 21.1% |
| Mayes County, OK | 72,292 | 17.3% |
| Ottawa County, OK | 69,145 | 23.1% |
| Ripley County, MO | 64,806 | 16.2% |
| Oregon County, MO | 61,115 | 12.1% |
| Christian County, MO | 59,104 | 16.4% |
| Barry County, MO | 56,096 | 11.3% |
| Independence County, AR | 54,126 | 11.1% |
| Searcy County, AR | 53,169 | 12.7% |
| Butler County, MO | 52,655 | 12.0% |
| Marion County, AR | 50,751 | 13.3% |
| Carroll County, AR | 48,559 | 12.0% |
| Madison County, MO | 48,510 | 15.3% |
| Newton County, MO | 46,022 | 11.5% |
| Calhoun County, AL | 45,183 | 13.0% |
| Iron County, MO | 44,436 | 12.6% |
| Camden County, MO | 42,783 | 10.2% |
| Boone County, AR | 40,942 | 10.9% |
| Stone County, AR | 38,635 | 10.0% |
| Washington County, AR | 36,356 | 6.0% |
| Bollinger County, MO | 33,384 | 8.5% |
| DeKalb County, AL | 33,150 | 7.6% |
| Union County, TN | 33,018 | 23.0% |
| Madison County, AR | 32,576 | 6.1% |
| Claiborne County, TN | 24,649 | 8.9% |
| McDonald County, MO | 22,860 | 6.6% |
| Newton County, AR | 21,763 | 4.1% |
| Stone County, MO | 21,023 | 7.1% |
| Baxter County, AR | 20,196 | 5.7% |
| Lawrence County, MO | 19,713 | 5.0% |
| Douglas County, MO | 18,887 | 3.6% |
| Howell County, MO | 17,686 | 3.0% |
| Bradley County, TN | 13,831 | 6.7% |
| Cape Girardeau County, MO | 13,703 | 3.8% |
| Randolph County, AR | 13,702 | 3.3% |
| Sharp County, AR | 11,633 | 3.0% |
| Taney County, MO | 9,908 | 2.5% |
| Texas County, MO | 9,754 | 1.3% |
| Union County, IL | 8,980 | 3.7% |
| Alexander County, IL | 8,647 | 6.3% |
| Hancock County, TN | 8,580 | 6.0% |
| Metcalfe County, KY | 7,986 | 4.3% |
| Cherokee County, KS | 7,669 | 2.0% |
| Lawrence County, AR | 6,830 | 1.8% |
| Izard County, AR | 5,888 | 1.6% |
| Webster County, MO | 5,526 | 1.5% |
| Perry County, MO | 5,291 | 1.8% |
| Craig County, OK | 4,910 | 1.0% |
| Ozark County, MO | 4,835 | 1.0% |
Septic absorption fields
NRCS rating, share of Clarksville acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 16.0% |
| Very limited | 84.0% |
Drainage, water table and flooding
Share of Clarksville 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 6–35% (median 30%).
- Topsoil organic matter
- Median 3.6%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 4.8% |
| Somewhat excessively drained | 94.8% |
| Well drained | 0.4% |
| 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) | 27.1% |
| B: moderate infiltration | 67.6% |
| C: slow infiltration | 4.8% |
| 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 Clarksville (component kind "Series") in SSURGO: 2,802,758 acres.
- Method
- Shares are by mapped acres of Clarksville components. The profile comes from the single largest Clarksville component. Full methodology.