Counties with the Highest Radon Potential in Massachusetts
The top 14 of 14 Massachusetts counties on GIS Map, ranked by EPA radon zone, where zone 1 carries the highest predicted indoor radon potential and zone 3 the lowest.
| # | County | EPA radon zone |
|---|---|---|
| 1 | Suffolk County | 3 |
| 2 | Barnstable County | 2 |
| 3 | Berkshire County | 2 |
| 4 | Bristol County | 2 |
| 5 | Dukes County | 2 |
| 6 | Franklin County | 2 |
| 7 | Hampden County | 2 |
| 8 | Hampshire County | 2 |
| 9 | Nantucket County | 2 |
| 10 | Norfolk County | 2 |
| 11 | Plymouth County | 2 |
| 12 | Essex County | 1 |
| 13 | Middlesex County | 1 |
| 14 | Worcester County | 1 |
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 Massachusetts”, https://gismap.land/rankings/massachusetts/highest-radon-counties. Figures from EPA Map of Radon Zones (September 2025).
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