Skip to content
RADON411

Locations and reports

Radon Levels in Henry County, Ohio

EPA puts Henry County in Zone 2, its middle radon zone, and high results are common there: 61.8% of the 34 radon tests reported to CDC (2008 to 2017, laboratory totals) came back 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

    61.8%

    9.5 pts above OH

    Henry
    61.8%
    Ohio
    52.3%

    34 tests, 2008 to 2017

  • Median result

    5.3pCi/L

    Action level reached

    Henry
    5.3 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    34

    79th of 79 by tests

    Henry
    34
    Franklin
    16,142

    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 Ohio

    22 of 79

    Middle half

    Henry
    61.8%
    Pickaway
    81.4%

    By share, of 79 with 30+ tests

Read a result for Henry County

Starts at Henry County's median, 5.3 pCi/L

5.3pCi/L

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

EPA’s reading of 5.3 pCi/L

At or above 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 at or above 4 pCi/L. EPA recommends fixing a home when the radon level is 4 pCi/L or higher. Henry County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Henry County, At a glance

Henry County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Henry 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: High across 74% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

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

Reported results by concentration band, Henry County, 2008 to 2017, laboratory
Under 2 pCi/L: 15%2 to 4 pCi/L: 23%4 pCi/L and above: 62%

Of 34 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Henry County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L514.7%
2 to 4 pCi/L823.5%
4 pCi/L and above2161.8%
What these figures count

These are the 34 tests reported to CDC for Henry 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

Henry County, Compared

Henry County radon figures, compared

Calculated by Radon411

More than half: 61.8% of the 34 radon tests reported to CDC for Henry County over the 2008 to 2017 laboratory totals read at least 4 pCi/L. That places it 22nd of 79 Ohio counties with 30 or more tests for the same period. That is 9.5 points above the 52.3% pooled from 88 Ohio counties.

The median result, 5.3 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 20.2 pCi/L. The rest split 14.7% under 2 pCi/L and 23.5% from 2 to 4 (Ohio: 23.1% and 24.6%). The reported tests do not follow EPA's Zone 2 label for Henry County (predicted average between 2 and 4 pCi/L): 61.8% of them reached 4 pCi/L, fewer than that label suggests.

No bordering county with a figure for the same period reported a higher share; the closest is Putnam County at 59.6%, the lowest Lucas County at 40.2%. Statewide for the same period, Pickaway County reported the highest share (81.4%) and Cuyahoga County the lowest (21.7%).

CDC's ten-year totals for Henry County went from 32 tests (2005 to 2014) to 34 (2008 to 2017), the share going from 56.3% to 61.8%.

Nationally, every county with a figure for the same period pools to 35.7%; Henry County sits 26.1 points above it. CDC also counts 9 tests taken after mitigation in Henry County for the same period: tests in homes where a fix was already in.

Henry County against Ohio, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Henry County
Henry County3461.8%5.3 pCi/LThis county
Ohio, pooled88 counties, pooled98,84052.3%Not pooled−9.5 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled−26.1 points
Pickaway Countyhighest in the state18381.4%9.5 pCi/L+19.6 points
Cuyahoga Countylowest in the state10,09221.7%2.0 pCi/L−40.1 points
Putnam County, OHborders it9459.6%4.8 pCi/L−2.2 points
Defiance County, OHborders it7048.6%3.8 pCi/L−13.2 points
Hancock County, OHborders it1,38246.2%3.7 pCi/L−15.6 points
Wood County, OHborders it1,19245.5%3.5 pCi/L−16.3 points
Fulton County, OHborders it6245.2%3.1 pCi/L−16.6 points
Williams County, OHborders it2842.9%3.3 pCi/L−18.9 points
Lucas County, OHborders it1,38140.2%3.0 pCi/L−21.6 points
Where Henry County's reported results fell, 2008 to 2017, laboratory, beside Ohio and the United States
ResultHenry County testsHenry County shareOhio shareU.S. shareAgainst Ohio
Under 2 pCi/L514.7%23.1%39.6%−8.4 points
2 to 4 pCi/L823.5%24.6%24.7%−1.1 points
4 pCi/L and above2161.8%52.3%35.7%+9.5 points
Henry County ranked among the 79 Ohio counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Darke County17 of 7927063.7%5.6 pCi/L
Ashland County18 of 7934062.9%5.4 pCi/L
Preble County19 of 7921262.7%5.5 pCi/L
Richland County20 of 791,32762.2%5.2 pCi/L
Wayne County21 of 791,07461.8%4.9 pCi/L
Henry County22 of 793461.8%5.3 pCi/L
Union County23 of 791,28560.2%4.8 pCi/L
Stark County24 of 793,31760.1%4.9 pCi/L
Shelby County25 of 7924860.1%5.2 pCi/L
Putnam County26 of 799459.6%4.8 pCi/L
Crawford County27 of 7921059.5%4.7 pCi/L
Henry County ten-year laboratory totals, against Ohio's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestOhio, pooledChange from the row before
2008 to 20173461.8%5.3 pCi/L20.2 pCi/L52.3%+4.2 points
2007 to 20163357.6%4.9 pCi/L15.1 pCi/L52.8%+1.3 points
2006 to 20153256.3%5.1 pCi/L15.1 pCi/L52.9%Level
2005 to 20143256.3%5.1 pCi/L15.1 pCi/L52.4%First on file

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

Henry County, Geology

The ground under Henry County

Predicted

USGS's geologic map splits Henry County: 74.3% of its land is high radon potential and 25.7% moderate. The map puts 74.3% of Henry County in the area it calls Till Plains and 25.7% in Lake Plains. USGS gives the first a radon index of 14, in the high band (12 to 17), and the second 10, in the moderate band (9 to 11).

USGS's geologic areas under Henry County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Till PlainsGlacial deposits underlain by Ordovician through Devonian limestone and shale.High1474.3%
Lake PlainsGlacial lake deposits, Devonian shale and limestone.Moderate1025.7%

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

Henry County beside the ground around it

Henry County has more high-potential ground than Ohio as a whole: 74.3% of its land against 62.8%. Of the 7 counties that border it, 3 have more high-potential ground, Hancock County the most at 100%.

Share of land by USGS radon potential: Henry County, the 7 counties bordering it and Ohio
AreaEPA zoneLow potentialModerate potentialHigh potential
Henry CountyZone 2None25.7%74.3%
Putnam CountyZone 2None32.3%67.7%
Fulton CountyZone 2None64.9%35.1%
Wood CountyZone 2None8.3%91.7%
Defiance CountyZone 2None37.4%62.6%
Hancock CountyZone 1NoneNone100%
Lucas CountyZone 2None85.6%13.9%
Williams CountyZone 2None9.7%90.3%
Ohio88 counties, pooled by land areaVariesNone37.2%62.8%

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

Local help

Henry County, Local resources

Radon testing and mitigation in Henry County

What Ohio's program says
Phone
614-728-0272
Email
indoor.radon@odh.ohio.gov
Licensing of radon professionals
This program licenses companies and persons directly involved with the radon testing and mitigation industry.

What it means

Henry County, Questions

Questions about radon in Henry County

Are radon levels high in Henry County?

Over the 2008 to 2017 laboratory totals, 61.8% of the radon tests reported to CDC for Henry County, Ohio were at or above 4 pCi/L, and the median reported pre-mitigation result was 5.3 pCi/L. Of 79 Ohio counties with 30 or more tests for the same period, 21 reported a higher share; pooled, the state comes to 52.3%.

Which counties border Henry County?

Henry County borders 7 counties: Putnam County, Fulton County, Wood County, Defiance County, Hancock County, Lucas County and Williams County.

Products

Henry County, Products

Testing a home in Henry County

In Henry County, 61.8% of 34 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 52.3% pooled across Ohio. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Henry County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Henry County homes, compared

Explore

Henry County, Bordering counties

Counties bordering Henry County

Calculated by Radon411

Henry County, Cities and towns

Cities and towns in Henry County

Henry County's population has barely moved since 2020: 27,598 residents on July 1, 2025 against 27,663 then, by the Census Bureau's estimates. That works out to 66 people per square mile of land. Its largest town, Napoleon, has 8,680 residents, 31.5% of the total. Together its 9 incorporated places hold 51.5% of those residents; the other 48.5% live outside any of them. Reported testing is thin here: 34 tests over 2008 to 2017, or 1.2 for every 1,000 residents (2025 estimate), where Ohio as a whole comes to 8.3.

From Napoleon to New Bavaria, CDC publishes no figure by town: each reads Henry County's.

The cities and towns in Henry County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Napoleon8,680−2.0%31.5%
Deshler1,576−0.8%5.7%
Liberty Center1,094−1.4%4.0%
Holgate1,050−1.1%3.8%
McClure694−0.4%2.5%
Hamler599−0.7%2.2%
Malinta229−2.1%0.8%
Florida217−1.8%0.8%
New Bavaria84−3.4%0.3%

9 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).

Henry County, Homes

Homes in Henry County

Henry County is a place of houses on their own lots: 81% of its 12,053 homes are detached single-family houses, against 69% across Ohio. Half of its homes were built before 1963, close to Ohio's 1970: 47% date from before 1960 and 9% from 2000 or later. Owners live in 82% of the occupied homes (Ohio: 67%), so for most households a test and a fix are their own to order.

Homes in Henry County, Ohio, 2019 to 2023
HomesHenry CountyOhio
Housing units12,0535,271,573
Detached houses81%69%
In buildings of 5 or more5%15%
Mobile homes7%4%
Built before 196047%38%
Built since 20009%16%
Middle year built19631970
Owner-occupied82%67%

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