Ranking · counties
The 25 US counties with the most acidic soil
The most acidic topsoil in the country is in Dare County, NC, with a typical pH of 3.5. North Carolina has more counties on this list than any other state (8 of 25).
- Lowest county pH
- 3.5
- Dare County, NC
- 25th on the list
- 4.6
- Bradford County, FL
- Counties ranked
- 2,906
- with enough rated land
The 25 most acidic counties
Typical topsoil pH, lowest first
| County | Typical pH | Strongly acidic land | Most common soil |
|---|---|---|---|
| 1. Dare County, NC | 3.5 | 72% | Pungo |
| 2. Tyrrell County, NC | 3.5 | 89% | Pungo |
| 3. Hyde County, NC | 3.7 | 76% | Pungo |
| 4. Piscataquis County, ME | 4.2 | 75% | Telos |
| 5. Aroostook County, ME | 4.3 | 74% | Howland |
| 6. Charles County, MD | 4.3 | 94% | Beltsville |
| 7. Boone County, WV | 4.3 | 87% | Matewan |
| 8. McDowell County, WV | 4.3 | 90% | Pineville |
| 9. Penobscot County, ME | 4.4 | 64% | Plaisted |
| 10. Logan County, WV | 4.4 | 67% | Matewan |
| 11. Mingo County, WV | 4.4 | 69% | Matewan |
| 12. Nicholas County, WV | 4.4 | 85% | Clifftop |
| 13. Kusilvak Census Area, AK | 4.5 | 66% | E40-maritime tussock-scrub-silty frozen slopes |
| 14. Northwest Arctic Borough, AK | 4.5 | 50% | E43-Arctic tussock-scrub-silty slopes, frozen |
| 15. Somerset County, ME | 4.5 | 78% | Monarda |
| 16. Gogebic County, MI | 4.5 | 80% | Gogebic |
| 17. Camden County, NC | 4.5 | 58% | Dorovan |
| 18. Jones County, NC | 4.5 | 86% | Croatan |
| 19. Perquimans County, NC | 4.5 | 80% | Roanoke |
| 20. Swain County, NC | 4.5 | 85% | Soco |
| 21. Washington County, NC | 4.5 | 70% | Belhaven |
| 22. Clinton County, PA | 4.5 | 70% | Hazleton |
| 23. Forest County, PA | 4.5 | 90% | Cookport |
| 24. Baker County, FL | 4.6 | 70% | Pamlico |
| 25. Bradford County, FL | 4.6 | 66% | Pelham |
What makes these soils so acidic
These counties combine heavy rainfall with old, well-weathered soils or sandy and organic soils that hold little calcium to begin with. Pine and oak forest litter adds more acidity at the surface. Coastal plain counties with sandy soils show up for the same reason: sand drains fast, so rain leaches it quickly.
Living with acidic soil
Below about pH 5.5, aluminum and manganese become more available to roots and phosphorus less so, which is why lawns thin out and vegetables stall. Garden lime raises pH slowly, over months, and the amount depends on soil texture: clay needs more than sand to move the same distance. A lab test from your county extension office tells you how much. If you would rather work with the soil, blueberries, azaleas, rhododendrons, camellias and hydrangeas (blue flowers) thrive in it.
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
- County rankings include counties with at least 100,000 acres of mapped land and soil ratings on at least 80% of it, so a small county with one unusual map unit cannot top the list. Counties without a full report on this site are named but not linked; the ZIP lookup covers them. Counties also need a pH reading on at least half their land. Typical pH is the area-weighted median of the first mineral horizon. Full methodology.