Soil series profile
Kennebec soil series
Kennebec is a moderately well drained soil with a silt loam surface, mapped on 799,711 acres in 121 counties across 6 states. Hydrologic group C.
- Drainage class
- Moderately well drained 100% of mapped acres
- Hydrologic group
- C 59% of mapped acres
- Typical topsoil pH
- 6.2 slightly acidic · range 6.1–6.5
- Mapped area
- 800k acres in 121 counties, 6 states
Typical Kennebec profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–8 in (Ap) | Silt loam | 6.2 | 25% | 7% | 3% |
| 8–41 in (A) | Silt loam | 6.3 | 24% | 6% | 2.5% |
| 41–54 in (AC) | Silty clay loam | 6.4 | 28% | 4% | 1.5% |
| 54–79 in (C) | Silty clay loam | 7.0 | 29% | 4% | 1% |
What this means
What Kennebec soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Kennebec soils is slightly acidic: pH 6.2 (most land between 6.1 and 6.5), the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Kennebec acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (94% of mapped Kennebec acres).
100% of mapped Kennebec acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 59% 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 >99% of the acres in mapped Kennebec soils very limited, <1% 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.
Flooding is mapped on >99% of the acres (73% occasional, 16% frequent).
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Kennebec soil is found
Mapped acres
Kennebec is mapped in Kansas, Iowa, Nebraska, Missouri, South Dakota and Minnesota. The 60 counties with the most Kennebec acres:
| County | Acres | Share of county land |
|---|---|---|
| Nemaha County, KS | 45,697 | 10.0% |
| Jackson County, KS | 40,296 | 9.6% |
| Marshall County, KS | 39,043 | 6.8% |
| Pottawatomie County, KS | 38,610 | 7.1% |
| Lancaster County, NE | 28,467 | 5.3% |
| Brown County, KS | 25,429 | 7.0% |
| Plymouth County, IA | 24,726 | 4.5% |
| Jefferson County, KS | 23,315 | 6.8% |
| Richardson County, NE | 20,958 | 6.0% |
| Ida County, IA | 20,135 | 7.3% |
| Leavenworth County, KS | 18,185 | 6.1% |
| Atchison County, KS | 17,208 | 6.2% |
| Jackson County, MO | 17,101 | 4.4% |
| Douglas County, KS | 16,907 | 5.8% |
| Harrison County, IA | 15,355 | 3.5% |
| Gage County, NE | 15,301 | 2.8% |
| Shawnee County, KS | 14,289 | 4.1% |
| Johnson County, KS | 14,255 | 4.7% |
| Crawford County, IA | 13,146 | 2.9% |
| Washington County, NE | 12,238 | 4.9% |
| Thurston County, NE | 11,643 | 4.6% |
| Doniphan County, KS | 11,624 | 4.6% |
| Union County, SD | 11,513 | 3.9% |
| Worth County, MO | 11,427 | 6.7% |
| Pawnee County, NE | 11,215 | 4.1% |
| Page County, IA | 10,258 | 3.0% |
| Wayne County, NE | 9,856 | 3.5% |
| Nodaway County, MO | 9,798 | 1.8% |
| Fremont County, IA | 9,702 | 3.0% |
| Platte County, MO | 9,191 | 3.4% |
| Riley County, KS | 8,761 | 2.2% |
| Dixon County, NE | 8,499 | 2.8% |
| Monona County, IA | 8,419 | 1.9% |
| Mills County, IA | 8,168 | 2.9% |
| Cuming County, NE | 8,031 | 2.2% |
| DeKalb County, MO | 7,735 | 2.9% |
| Douglas County, NE | 7,728 | 3.7% |
| Woodbury County, IA | 7,558 | 1.4% |
| Pottawattamie County, IA | 7,227 | 1.2% |
| Dodge County, NE | 7,135 | 2.1% |
| Lafayette County, MO | 7,014 | 1.7% |
| Johnson County, NE | 6,739 | 2.8% |
| Warren County, IA | 5,839 | 1.6% |
| Sarpy County, NE | 5,684 | 3.7% |
| Sac County, IA | 5,568 | 1.5% |
| Burt County, NE | 5,349 | 1.7% |
| Goodhue County, MN | 4,876 | 1.0% |
| Clinton County, MO | 4,524 | 1.7% |
| Cass County, IA | 4,363 | 1.2% |
| Caldwell County, MO | 4,332 | 1.6% |
| Shelby County, IA | 4,247 | 1.1% |
| Dakota County, NE | 3,963 | 2.3% |
| Buchanan County, MO | 3,959 | 1.5% |
| Montgomery County, IA | 3,905 | 1.4% |
| Morris County, KS | 3,883 | 0.9% |
| Madison County, IA | 3,794 | 1.1% |
| Cass County, NE | 3,773 | 1.1% |
| Schuyler County, MO | 3,770 | 1.9% |
| Harrison County, MO | 3,476 | 0.8% |
| Adair County, IA | 3,371 | 0.9% |
Septic absorption fields
NRCS rating, share of Kennebec acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 0.9% |
| Very limited | 99.1% |
Drainage, water table and flooding
Share of Kennebec acres
- Depth to seasonal high water table
- About 3.4 feet (41 in) (median where reported).
- Flooding
- Mapped as flooding on >99% of acres (73% occasional, 16% frequent).
- Slope
- Typically 1–2% (median 1%).
- 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 | 0.0% |
| Moderately well drained | 100.0% |
| 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 | 41.1% |
| C: slow infiltration | 58.9% |
| 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 Kennebec (component kind "Series") in SSURGO: 799,711 acres.
- Method
- Shares are by mapped acres of Kennebec components. The profile comes from the single largest Kennebec component. Full methodology.