Alaska: 30 counties covered
Of 23 rated Alaska counties, 0 are in EPA's highest radon-potential zone (Zone 1) — but every county page links to testing guidance regardless of zone, because a county rating is a county-wide average, not a reading for any one house.
- Anchorage Municipality
- Matanuska-Susitna Borough
- Fairbanks North Star Borough
- Kenai Peninsula Borough
- Juneau City and Borough
- Bethel Census Area
- Ketchikan Gateway Borough
- Kodiak Island Borough
- North Slope Borough
- Nome Census Area
- Sitka City and Borough
- Kusilvak Census Area
- Southeast Fairbanks Census Area
- Northwest Arctic Borough
- Chugach Census Area
- Prince of Wales-Hyder Census Area
- Aleutians West Census Area
- Yukon-Koyukuk Census Area
- Dillingham Census Area
- Aleutians East Borough
- Petersburg Borough
- Copper River Census Area
- Hoonah-Angoon Census Area
- Haines Borough
- Wrangell City and Borough
- Denali Borough
- Lake and Peninsula Borough
- Skagway Municipality
- Bristol Bay Borough
- Yakutat City and Borough