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Counties with the Highest Radon Potential in Wisconsin

The top 25 of 72 Wisconsin counties on GIS Map, ranked by EPA radon zone, where zone 1 carries the highest predicted indoor radon potential and zone 3 the lowest.

#CountyEPA radon zone
1Adams County
2
2Ashland County
2
3Barron County
2
4Bayfield County
2
5Brown County
2
6Burnett County
2
7Calumet County
2
8Chippewa County
2
9Clark County
2
10Columbia County
2
11Douglas County
2
12Dunn County
2
13Eau Claire County
2
14Florence County
2
15Forest County
2
16Iron County
2
17Jackson County
2
18Juneau County
2
19Kenosha County
2
20Kewaunee County
2
21La Crosse County
2
22Lincoln County
2
23Manitowoc County
2
24Marinette County
2
25Marquette County
2

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 Wisconsin”, https://gismap.land/rankings/wisconsin/highest-radon-counties. Figures from EPA Map of Radon Zones (September 2025).

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