Reference · metro counties
The soil under America's 25 most populous counties
Soil surveys cover cities too, even if much of the soil is under pavement. Of the 25 most populous counties, New York County, NY has the most land mapped as urban land (72%), where the original soil has been dug up, filled or covered.
- Counties
- 25
- most populous
- Most urban land
- 72%
- New York County, NY
Soil in the 25 most populous counties
By population
| County | Most common named soil | Typical pH | Well drained | Septic very limited | Urban land |
|---|---|---|---|---|---|
| Los Angeles County, CA | Millsholm family | 6.6 | 82% | 81% | 11% |
| Cook County, IL | Ozaukee | 6.7 | 40% | 69% | 30% |
| Harris County, TX | Lake Charles | 6.0 | 25% | 82% | 21% |
| Maricopa County, AZ | Gunsight | 8.2 | 83% | 47% | 0% |
| San Diego County, CA | Cieneba | 6.5 | 77% | 83% | 0% |
| Orange County, CA | Cieneba | 7.3 | 73% | 77% | 0% |
| Miami-Dade County, FL | Biscayne | 7.9 | 11% | 61% | 26% |
| Dallas County, TX | Houston Black | 7.9 | 83% | 83% | 15% |
| Kings County, NY | Nagunt | 6.2 | 24% | 81% | 62% |
| Riverside County, CA | Carsitas | 7.0 | 75% | 77% | 0% |
| Clark County, NV | Weiser | 8.2 | 90% | 77% | 0% |
| King County, WA | Alderwood | 5.6 | 84% | 93% | 5% |
| Queens County, NY | Greenbelt | 6.2 | 31% | 83% | 61% |
| Tarrant County, TX | Sanger | 7.8 | 89% | 70% | 12% |
| San Bernardino County, CA | Cajon | 7.9 | 86% | 71% | 0% |
| Bexar County, TX | Eckrant | 7.8 | 98% | 86% | 0% |
| Broward County, FL | Shark Valley | 5.8 | 4% | 91% | 9% |
| Santa Clara County, CA | Gaviota | 6.5 | 78% | 81% | 13% |
| Wayne County, MI | Tedrow | 6.7 | 14% | 75% | 18% |
| Middlesex County, MA | Charlton | 5.1 | 63% | 81% | 10% |
| New York County, NY | Greenbelt | 6.2 | 26% | 90% | 72% |
| Alameda County, CA | Vallecitos | 6.7 | 65% | 76% | 0% |
| Sacramento County, CA | San Joaquin | 6.1 | 57% | 76% | 7% |
| Palm Beach County, FL | Terra Ceia | 6.0 | 3% | 98% | 0% |
| Hillsborough County, FL | Myakka | 5.1 | 17% | 93% | 4% |
Urban land on a soil map
"Urban land" is a soil survey category for ground so covered or disturbed that the original soil cannot be identified. Gardens in older neighborhoods often sit on fill: a mix of the original soil, construction debris and topsoil brought in later. That is a good reason to test city garden soil for lead as well as pH before growing vegetables.
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 mapped land in the 50 states and DC in the current soil survey.
- Method
- Population: Census Bureau county estimates (Vintage 2024). Most common named soil skips miscellaneous areas such as urban land and water. Urban land counts every map unit component named urban land. Full methodology.