Wyoming Cities Ranked by Indoor Radon Levels
Measured averages from Airthings devices across Wyoming, USA. Action level: 4 pCi/L — the threshold at which remediation is recommended.
Afton has the highest measured indoor radon in Wyoming at 9.3 pCi/L, based on Airthings measurements across 21 cities.
Updated August 16, 2026
Highest city
9.3pCi/L
Afton
Wyoming city average
4.2pCi/L
across 21 cities
Above action level
10/ 21
cities
| # | Location | Avg level | Monitors | vs action level |
|---|---|---|---|---|
| 1 | Afton | 9.3 pCi/L | 16 | 2.3× over |
| 2 | Rafter J Ranch | 7.8 pCi/L | 8 | 2.0× over |
| 3 | Riverton | 5.5 pCi/L | 8 | 1.4× over |
| 4 | Jackson | 5.4 pCi/L | 43 | 1.3× over |
| 5 | Sheridan | 5.4 pCi/L | 25 | 1.3× over |
| 6 | Mills | 5.3 pCi/L | 14 | 1.3× over |
| 7 | Lander | 5.3 pCi/L | 8 | 1.3× over |
| 8 | Cody | 5.3 pCi/L | 24 | 1.3× over |
| 9 | Pinedale | 4.5 pCi/L | 12 | 1.1× over |
| 10 | Douglas | 4.4 pCi/L | 13 | 1.1× over |
| ✓ Below EPA action level (4 pCi/L) | ||||
| 11 | Evansville | 3.8 pCi/L | 10 | 1.0× under |
| 12 | Casper | 3.5 pCi/L | 20 | 0.9× under |
| 13 | Laramie | 3.5 pCi/L | 57 | 0.9× under |
| 14 | Gillette | 3.3 pCi/L | 28 | 0.8× under |
| 15 | Wilson | 2.9 pCi/L | 7 | 0.7× under |
| 16 | Fox Farm-College | 2.9 pCi/L | 11 | 0.7× under |
| 17 | Rock Springs | 2.6 pCi/L | 9 | 0.7× under |
| 18 | Ranchettes | 2.3 pCi/L | 18 | 0.6× under |
| 19 | Cheyenne | 2.2 pCi/L | 34 | 0.5× under |
| 20 | Moose Wilson Road | 2.1 pCi/L | 13 | 0.5× under |
| 21 | Hoback | 1.5 pCi/L | 9 | 0.4× under |