| # | County | EPA radon zone |
|---|---|---|
| 1 | Arkansas County | 3 |
| 2 | Ashley County | 3 |
| 3 | Bradley County | 3 |
| 4 | Calhoun County | 3 |
| 5 | Chicot County | 3 |
| 6 | Clark County | 3 |
| 7 | Clay County | 3 |
| 8 | Cleburne County | 3 |
| 9 | Cleveland County | 3 |
| 10 | Columbia County | 3 |
| 11 | Conway County | 3 |
| 12 | Craighead County | 3 |
| 13 | Crawford County | 3 |
| 14 | Crittenden County | 3 |
| 15 | Cross County | 3 |
| 16 | Dallas County | 3 |
| 17 | Desha County | 3 |
| 18 | Drew County | 3 |
| 19 | Faulkner County | 3 |
| 20 | Franklin County | 3 |
| 21 | Grant County | 3 |
| 22 | Greene County | 3 |
| 23 | Hempstead County | 3 |
| 24 | Hot Spring County | 3 |
| 25 | Howard County | 3 |
Source: EPA Map of Radon Zones (September 2025). All counties with data are ranked. Estimates carry margins of error.
Citing this page: GIS Map, “Counties with the Highest Radon Potential in Arkansas”, https://gismap.land/rankings/arkansas/highest-radon-counties. Figures from EPA Map of Radon Zones (September 2025).
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