Soil series profile
Miamian soil series
Miamian is a well drained soil with a silt loam surface, mapped on 757,634 acres in 38 counties across 2 states. Hydrologic group C.
- Drainage class
- Well drained 98% of mapped acres
- Hydrologic group
- C 98% of mapped acres
- Typical topsoil pH
- 6.5 slightly acidic · range 6.5–6.5
- Mapped area
- 758k acres in 38 counties, 2 states
Typical Miamian profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–10 in (Ap) | Silt loam | 6.5 | 21% | 24% | 2% |
| 10–14 in (Bt1) | Silty clay loam | 6.2 | 30% | 14% | 0.75% |
| 14–36 in (2Bt2) | Clay | 6.5 | 42% | 28% | 0.65% |
| 36–79 in (2Cd) | Loam | 7.9 | 24% | 36% | 0.3% |
What this means
What Miamian soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Miamian soils is slightly acidic: pH 6.5, the range most vegetables, flowers and lawn grasses prefer.
Loamy topsoil (loam, silt loam and similar) covers 99% of mapped Miamian acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (89% of mapped Miamian acres).
>99% of mapped Miamian 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 97% of the acres in mapped Miamian soils very limited, <1% somewhat limited and 2% not limited (1% not rated, such as urban land, pits or water).
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 Miamian soil is found
Mapped acres
Miamian is mapped in Ohio and Indiana.
| County | Acres | Share of county land |
|---|---|---|
| Montgomery County, OH | 68,070 | 23.1% |
| Greene County, OH | 58,530 | 22.0% |
| Pickaway County, OH | 55,807 | 17.4% |
| Ross County, OH | 51,521 | 11.7% |
| Preble County, OH | 51,181 | 18.9% |
| Clark County, OH | 48,455 | 19.1% |
| Darke County, OH | 47,247 | 12.3% |
| Logan County, OH | 45,479 | 15.4% |
| Miami County, OH | 37,531 | 14.4% |
| Butler County, OH | 36,702 | 12.4% |
| Fayette County, OH | 36,623 | 14.1% |
| Highland County, OH | 33,924 | 9.6% |
| Henry County, IN | 31,921 | 12.7% |
| Clinton County, OH | 31,460 | 12.0% |
| Rush County, IN | 26,089 | 10.0% |
| Warren County, OH | 21,250 | 8.3% |
| Madison County, OH | 16,983 | 5.7% |
| Champaign County, OH | 12,669 | 4.6% |
| Franklin County, OH | 12,399 | 3.6% |
| Delaware County, IN | 8,978 | 3.6% |
| Shelby County, OH | 6,537 | 2.5% |
| Fairfield County, OH | 5,202 | 1.6% |
| Shelby County, IN | 3,924 | 1.5% |
| Hancock County, IN | 3,895 | 2.0% |
| Randolph County, IN | 1,039 | 0.4% |
| Hamilton County, OH | 940 | 0.4% |
| Wayne County, IN | 884 | 0.4% |
| Union County, OH | 839 | 0.3% |
| Bartholomew County, IN | 722 | 0.3% |
| Decatur County, IN | 263 | 0.1% |
| Fayette County, IN | 155 | 0.1% |
| Madison County, IN | 136 | 0.0% |
| Pike County, OH | 114 | 0.0% |
| Grant County, IN | 64 | 0.0% |
| Franklin County, IN | 55 | 0.0% |
| Johnson County, IN | 38 | 0.0% |
| Union County, IN | 7 | 0.0% |
| Allen County, IN | 0 | 0.0% |
Septic absorption fields
NRCS rating, share of Miamian acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 1.5% |
| Somewhat limited | 0.3% |
| Very limited | 97.1% |
| Not rated | 1.1% |
Drainage, water table and flooding
Share of Miamian acres
- Depth to seasonal high water table
- About 2.9 feet (35 in) (median where reported); within 18 inches on 1% of acres.
- Flooding
- Not mapped as flooding on most acres.
- Slope
- Typically 3–15% (median 4%).
- 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 | 98.1% |
| Moderately well drained | 1.2% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
| Not rated | 0.6% |
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 | 97.6% |
| D: very slow infiltration (clayey, shallow or wet) | 1.0% |
| 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 | 0.3% |
| Not rated | 1.1% |
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 Miamian (component kind "Series") in SSURGO: 757,634 acres.
- Method
- Shares are by mapped acres of Miamian components. The profile comes from the single largest Miamian component. Full methodology.