Ranking · states and counties
Where the US has the most organic matter in its topsoil
Typical topsoil in Alaska holds 10.0% organic matter, the most of any state, followed by Hawaii (6.6%). Outside Alaska, whose tundra census areas would fill a county list on their own, the county leader is Broward County, FL, at 75.0%: a sign of peat or muck rather than garden loam.
- Top state
- 10.0%
- Alaska
- Top county
- 75.0%
- Broward County, FL
- States at 3% or more
- 20
- typical topsoil organic matter
States with the most organic matter in topsoil
Typical topsoil, by weight
| State | Organic matter | Poorly drained land |
|---|---|---|
| 1. Alaska | 10.0% | 44% |
| 2. Hawaii | 6.6% | 4% |
| 3. Rhode Island | 6.4% | 18% |
| 4. Massachusetts | 6.0% | 18% |
| 5. Connecticut | 5.5% | 16% |
| 6. Vermont | 5.5% | 22% |
| 7. Minnesota | 5.0% | 55% |
| 8. New Hampshire | 5.0% | 14% |
| 9. New York | 4.5% | 27% |
| 10. Maine | 4.0% | 41% |
| 11. North Dakota | 4.0% | 26% |
| 12. Iowa | 3.5% | 45% |
| 13. Idaho | 3.0% | 4% |
| 14. Michigan | 3.0% | 45% |
| 15. New Jersey | 3.0% | 29% |
The 25 counties with the most organic topsoil
Outside Alaska
| County | Organic matter | Poorly drained land | Most common soil |
|---|---|---|---|
| 1. Broward County, FL | 75.0% | 87% | Shark Valley |
| 2. Palm Beach County, FL | 75.0% | 95% | Terra Ceia |
| 3. Koochiching County, MN | 65.0% | 87% | Greenwood |
| 4. Lake of the Woods County, MN | 65.0% | 87% | Cathro |
| 5. Dare County, NC | 57.5% | 84% | Pungo |
| 6. Lafourche Parish, LA | 50.0% | >99% | Allemands |
| 7. St. John the Baptist Parish, LA | 50.0% | 98% | Barbary |
| 8. Hyde County, NC | 50.0% | 89% | Pungo |
| 9. Tyrrell County, NC | 50.0% | 98% | Pungo |
| 10. Cameron Parish, LA | 45.5% | 96% | Allemands |
| 11. Plaquemines Parish, LA | 45.5% | >99% | Clovelly |
| 12. St. Bernard Parish, LA | 45.5% | >99% | Scatlake |
| 13. Jefferson Parish, LA | 45.0% | >99% | LaFitte |
| 14. Terrebonne Parish, LA | 45.0% | 96% | Kenner |
| 15. St. Charles Parish, LA | 40.0% | 98% | Kenner |
| 16. St. Mary Parish, LA | 13.5% | 94% | Baldwin |
| 17. Grays Harbor County, WA | 12.5% | 10% | Zenker |
| 18. Pacific County, WA | 12.5% | 9% | Elochoman |
| 19. Wahkiakum County, WA | 12.5% | 11% | Lytell |
| 20. Tillamook County, OR | 11.0% | 5% | Klootchie |
| 21. Bristol County, MA | 10.0% | 34% | Paxton |
| 22. Putnam County, NY | 10.0% | 15% | Charlton |
| 23. Avery County, NC | 10.0% | 2% | Porters |
| 24. Washington County, NC | 10.0% | 92% | Belhaven |
| 25. Clatsop County, OR | 10.0% | 9% | Rinearson |
More is not always better
Organic matter feeds soil life, holds water and makes soil crumbly, and 3% to 6% is a very good garden soil. Far above that, the soil is usually peat or muck formed in wetlands, where waterlogging slowed decay for centuries. That is why the top of the list is cold, wet country rather than prime farmland. The famous dark prairie soils of the Midwest sit in the comfortable middle.
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. Organic matter is percent by weight in the first mineral horizon (surface litter skipped), as the area-weighted median. Full methodology.