Radon zones in Maryland
| Allegany County | Maryland | 2 |
| Anne Arundel County | Maryland | 2 |
| Baltimore County | Maryland | 1 |
| Baltimore city | Maryland | 1 |
| Carroll County | Maryland | 1 |
| Cecil County | Maryland | 2 |
| Charles County | Maryland | 2 |
| Dorchester County | Maryland | 3 |
| Frederick County | Maryland | 1 |
| Garrett County | Maryland | 2 |
| Harford County | Maryland | 1 |
| Howard County | Maryland | 1 |
| Kent County | Maryland | 3 |
| Montgomery County | Maryland | 1 |
| Somerset County | Maryland | 3 |
| Talbot County | Maryland | 3 |
| Washington County | Maryland | 1 |
| Wicomico County | Maryland | 3 |
| Worcester County | Maryland | 3 |
Sources
- Maryland: EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- Maryland: EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- Maryland: EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- Maryland: EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- Maryland: EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- Maryland: EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
- EPA Map of Radon Zones, US Environmental Protection Agency, checked 1 November 2026
"Secondary" marks a source used only because the official page could not be read.