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Radon Levels in Iron County, Michigan

EPA puts Iron County in Zone 2, its middle radon zone, and 36.2% of its 265 reported radon tests (2008 to 2017, laboratory totals) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

How to test this homeFind a certified tester

  • Share at 4+ pCi/L

    36.2%

    9.3 pts above MI

    Iron
    36.2%
    Michigan
    26.9%

    265 tests, 2008 to 2017

  • Median result

    2.6pCi/L

    Below action level

    Iron
    2.6 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    265

    60th of 82 by tests

    Iron
    265
    Oakland
    16,224

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 2

    Moderate potential

    1. 1
    2. Zone 2
    3. 3

    1 highest, 3 lowest

    EPA predicts 2 to 4 pCi/L indoors

  • Rank in Michigan

    12 of 82

    Top quarter

    Iron
    36.2%
    Lenawee
    56.7%

    By share, of 82 with 30+ tests

Read a result for Iron County

Starts at Iron County's median, 2.6 pCi/L

2.6pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 2.6 pCi/L

Between 2 and 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Iron County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Iron County, At a glance

Iron County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Iron County is a county: EPA's forecast for it as a whole is an average indoor of 2 to 4 pCi/L (75 to 150 Bq/m³). It describes no single address, and homes above EPA's are found in every zone, this one included.

USGS geologic potential: Moderate across 100% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Iron County, 2008 to 2017, laboratory

Reported results by concentration band, Iron County, 2008 to 2017, laboratory
Under 2 pCi/L: 38%2 to 4 pCi/L: 26%4 pCi/L and above: 36%

Of 265 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Iron County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L10138.1%
2 to 4 pCi/L6825.7%
4 pCi/L and above9636.2%
What these figures count

These are the 265 tests reported to CDC for Iron County over 2008 to 2017 (laboratory totals), many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.

Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Iron County, Compared

Iron County radon figures, compared

Calculated by Radon411

In Iron County, about 4 in 10 reported tests over the 2008 to 2017 laboratory totals (96 of 265) were at or above EPA's action level. Against the national pool of 35.7%, the gap is 0.5 points higher. Across 83 Michigan counties pooled together, 26.9% of tests reached that level, so Iron County runs 9.3 points above its state.

Of 9 neighbours with a figure, 3 reported a larger share at or above 4 pCi/L and 6 a smaller one; the spread is 10.8% (Houghton County) to 55.6% (Forest County, WI). By share, Iron County is 12th of 82 Michigan counties with 30 or more tests for the same period.

Half the tests came in under 2.6 pCi/L and half over it; the single highest reached 66.6 pCi/L. Below the action level, 101 tests (38.1%) came in under 2 pCi/L, against 46.4% statewide, and 68 tests (25.7%) fell between 2 and 4, against 26.7% statewide.

Zone 2 on EPA's map (predicted average between 2 and 4 pCi/L) and a 36.2% share point the same way here. USGS geology rates 100% of the county's land moderate radon potential.

CDC's ten-year totals for Iron County went from 223 tests (2005 to 2014) to 265 (2008 to 2017), the share going from 36.8% to 36.2%.

Iron County against Michigan, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Iron County
Iron County26536.2%2.6 pCi/LThis county
Michigan, pooled83 counties, pooled114,40726.9%Not pooled−9.3 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−0.5 points
Lenawee Countyhighest in the state1,90756.7%4.6 pCi/L+20.5 points
Muskegon Countylowest in the state6293.2%1.2 pCi/L−33.0 points
Forest County, WIborders it8155.6%4.2 pCi/L+19.4 points
Florence County, WIborders it16552.1%4.3 pCi/L+15.9 points
Dickinson County, MIborders it84339.3%3.1 pCi/L+3.1 points
Vilas County, WIborders it50735.7%2.9 pCi/L−0.5 points
Marquette County, MIborders it1,08223.4%2.0 pCi/L−12.8 points
Gogebic County, MIborders it17112.9%1.2 pCi/L−23.3 points
Ontonagon County, MIborders it12311.4%1.3 pCi/L−24.8 points
Baraga County, MIborders it16311.0%1.1 pCi/L−25.2 points
Houghton County, MIborders it1,09310.8%1.1 pCi/L−25.4 points
Where Iron County's reported results fell, 2008 to 2017, laboratory, beside Michigan and the United States
ResultIron County testsIron County shareMichigan shareU.S. shareAgainst Michigan
Under 2 pCi/L10138.1%46.4%39.6%−8.3 points
2 to 4 pCi/L6825.7%26.7%24.7%−1.0 points
4 pCi/L and above9636.2%26.9%35.7%+9.3 points
Iron County ranked among the 82 Michigan counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Dickinson County7 of 8284339.3%3.1 pCi/L
Clinton County8 of 822,31338.5%3.1 pCi/L
Otsego County9 of 821,08038.2%3.2 pCi/L
Ionia County10 of 821,39136.8%2.9 pCi/L
Calhoun County11 of 821,64936.4%3.0 pCi/L
Iron County12 of 8226536.2%2.6 pCi/L
Tuscola County13 of 8236935.5%2.6 pCi/L
Eaton County14 of 823,41134.4%2.8 pCi/L
St. Joseph County15 of 821,06834.1%2.9 pCi/L
Lapeer County16 of 8264933.4%2.7 pCi/L
Kalamazoo County17 of 824,10033.3%2.8 pCi/L
Iron County ten-year laboratory totals, against Michigan's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestMichigan, pooledChange from the row before
2008 to 201726536.2%2.6 pCi/L66.6 pCi/L26.9%−1.1 points
2007 to 201624137.3%3.0 pCi/L66.6 pCi/L26.8%−0.4 points
2006 to 201522837.7%3.0 pCi/L36.4 pCi/L26.8%+0.9 points
2005 to 201422336.8%3.0 pCi/L36.4 pCi/L26.2%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Iron County, State data

Michigan's own radon test data

Measured

What Michigan's own agencies publish about radon tests in Iron County, with their period. These are not CDC's figures and are never added to them.

MeasuredState figures, not CDC's

What Michigan EGLE reports for the ZIP codes in Iron County

Michigan EGLE publishes its figures by ZIP code, not by county. These are the 8 ZIP codes that lie wholly or partly in Iron County, each with the state's own figures for it. Period: About 10 years to 2026-05-15.

ZIP codes in Iron County
ZIP codeWhat the state reports
4987965% greater than 4 pCi/L, median 5.0 pCi/L, 17 tests
499021 tests, figures not shown
499032 tests, figures not shown
499151 tests, figures not shown
4992049% greater than 4 pCi/L, median 3.5 pCi/L, 61 tests
499273 tests, figures not shown
4993524% greater than 4 pCi/L, median 1.6 pCi/L, 83 tests
499670% greater than 4 pCi/L, median 0.0 pCi/L, 5 tests
  • EGLE's figures cover first-time tests only, from organizations willing to provide data.
  • EGLE does not publish figures for a ZIP code with fewer than 5 test results.
  • EGLE says the map is not intended to decide whether a home should be tested: all homes should be tested.
  • ZIP code boundaries are postal delivery areas, not legal or administrative boundaries.
  • A ZIP code that crosses the county line is listed whole; its figures cover all of it.

Measured: Michigan EGLE data, About 10 years to 2026-05-15.

Iron County, Geology

The ground under Iron County

Predicted

USGS's geologic map puts all of Iron County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Marquette Highland/Keweenaw Peninsula/Gogebic Range, to which USGS gives a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Iron County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Marquette Highland/Keweenaw Peninsula/Gogebic RangeGranite, iron formtion, sandstone, conglomerate, metamorphic rocks, and glacial drift.Moderate1199.7%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Iron County beside the ground around it

Across Michigan 9.6% of the land is rated high; none of Iron County's is. Of the 9 counties that border it, 1 has more high-potential ground, Forest County, WI the most at 2.7%.

Share of land by USGS radon potential: Iron County, the 9 counties bordering it and Michigan
AreaEPA zoneLow potentialModerate potentialHigh potential
Iron CountyZone 2None100%None
Florence County, WIZone 2None100%None
Forest County, WIZone 2None97.3%2.7%
Dickinson CountyZone 2None100%None
Baraga CountyZone 2None99.9%None
Vilas County, WIZone 2None100%None
Marquette CountyZone 2None99.9%None
Houghton CountyZone 216.2%81.1%None
Ontonagon CountyZone 363.1%36.9%None
Gogebic CountyZone 216.3%83.7%None
Michigan83 counties, pooled by land areaVaries45.0%44.3%9.6%

The map rates the ground, not the air in any home.

Local help

Iron County, Local resources

Radon testing and mitigation in Iron County

What Michigan's program says
Phone
800-723-6642
Email
Radon@Michigan.gov
Licensing of radon professionals
Michigan does not license or regulate radon testing and mitigation contractors.

What it means

Iron County, Questions

Questions about radon in Iron County

Are radon levels high in Iron County?

Over the 2008 to 2017 laboratory totals, 36.2% of the radon tests reported to CDC for Iron County, Michigan were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.6 pCi/L. Of 82 Michigan counties with 30 or more tests for the same period, 11 reported a higher share; pooled, the state comes to 26.9%.

Which counties border Iron County?

Iron County borders 9 counties: Florence County, WI, Forest County, WI, Dickinson County, MI, Baraga County, MI, Vilas County, WI, Marquette County, MI, Houghton County, MI, Ontonagon County, MI and Gogebic County, MI.

Products

Iron County, Products

Testing a home in Iron County

In Iron County, 36.2% of 265 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 26.9% pooled across Michigan. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Iron County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Iron County homes, compared

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Iron County, Bordering counties

Counties bordering Iron County

Calculated by Radon411

Iron County, Cities and towns

Cities and towns in Iron County

The Census Bureau estimates 11,757 residents in Iron County for July 1, 2025, 127 more than in 2020 (+1.1%). That works out to 10 people per square mile of land. Its largest town, Iron River, has 3,027 residents, 25.7% of the total. Together its 5 incorporated places hold 50.1% of those residents; the other 49.9% live outside any of them. Testing is reported here more often than across the state: CDC's 265 reported tests for 2008 to 2017 come to 22.5 for every 1,000 residents (2025 estimate), against 11.3 for Michigan.

From Iron River to Alpha, CDC publishes no figure by town: each reads Iron County's.

The cities and towns in Iron County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Iron River3,027+0.7%25.7%
Crystal Falls1,607+0.8%13.7%
Caspian818+1.0%7.0%
Gaastra319+0.9%2.7%
Alpha124+0.8%1.1%

5 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025).

Iron County, Homes

Homes in Iron County

Iron County is a place of houses on their own lots: 88% of its 9,046 homes are detached single-family houses, against 72% across Michigan. The homes are older than Michigan's as a whole: half were built before 1962 (1972 for Michigan), and 48% date from before 1960. Owners live in 85% of the occupied homes (Michigan: 73%), so for most households a test and a fix are their own to order.

Homes in Iron County, Michigan, 2019 to 2023
HomesIron CountyMichigan
Housing units9,0464,599,683
Detached houses88%72%
In buildings of 5 or more4%13%
Mobile homes4%5%
Built before 196048%36%
Built since 200012%15%
Middle year built19621972
Owner-occupied85%73%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.