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Radon Levels in Lyon County, Kentucky

EPA puts Lyon County in Zone 2, its middle radon zone, and only 14 radon tests from it are on file with CDC (2008 to 2017, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

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  • Highest bordering

    22.2%

    Trigg County

    Trigg
    22.2%
    Marshall
    10.6%

    2 of 5 neighbours have 30+ tests, 2008 to 2017

  • Nearest county

    10.6%

    Marshall County, 17 miles

    Marshall
    10.6%
    Kentucky
    43.7%

    Share at 4+ pCi/L, 85 tests, 2008 to 2017

  • Ground above low

    100.0%

    5.7 pts above Kentucky

    Lyon
    100.0%
    Kentucky
    94.3%

    Share of land USGS rates moderate or high potential

  • Tests reported

    15

    Too few for a share

    Lyon
    15
    Needed
    30

    2006 to 2015, laboratory

  • 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

Read a result for Lyon County

Starts at EPA's action level

4.0pCi/L

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

EPA’s reading of 4.0 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.

Interpret this readingWhat a fix costs

The data

Lyon County, At a glance

Lyon County at a glance

Predicted: EPA radon zone

EPA Zone 2: moderate predicted potential

Lyon 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 Lyon County, 2008 to 2017, laboratory

CDC holds 14 reported tests for Lyon County over the 2008 to 2017 laboratory totals, with a median of 2.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Lyon County beside the counties around it is how this page reads it.

What these figures count

Only 14 tests were reported to CDC for Lyon County over 2008 to 2017 (laboratory totals), and tests are often run on homes being sold or already suspected of a problem: so few describe neither the county nor 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

Lyon County, Compared

Lyon County radon figures, compared

Calculated by Radon411

CDC's largest figure for Lyon County rests on 15 tests over the 2006 to 2015 laboratory totals, 4 of them at or above 4 pCi/L, so each test moves its share by 6.7 points and no rank or comparison is drawn from it. Results reached as high as 14.0 pCi/L, with a middle value of 2.5 pCi/L.

Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Trigg County reported the largest share at or above 4 pCi/L, 22.2%, and Marshall County the smallest, 10.6%. Farther out, Christian County (34 miles away) at 36.1%, Hopkins County (36 miles away) at 9.5% and Todd County (52 miles away) at 17.7% have figures too. Pooled across 120 Kentucky counties, 43.7% of reported tests reached that level; across every county in the country with a figure, 35.7%.

Statewide for the same period, Meade County reported the highest share (68.4%) and Hopkins County the lowest (9.5%). EPA's 1993 map puts Lyon County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 100% of the county's land moderate radon potential.

Kentucky, the United States and the counties around Lyon County, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedian
Kentucky, pooled120 counties, pooled28,79343.7%Not pooled
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled
Meade Countyhighest in the state11768.4%8.2 pCi/L
Hopkins Countylowest in the state429.5%1.7 pCi/L
Caldwell County, KYborders it2040.0%3.7 pCi/L
Crittenden County, KYborders it825.0%1.6 pCi/L
Trigg County, KYborders it4522.2%2.4 pCi/L
Marshall County, KYborders it8510.6%1.5 pCi/L
Livingston County, KYborders it110.0%1.3 pCi/L
The nearest Kentucky counties to Lyon County with 30 or more tests, 2008 to 2017, laboratory
CountyDistanceTestsAt or above 4 pCi/LMedian
Marshall County17 mi8510.6%1.5 pCi/L
Trigg County19 mi4522.2%2.4 pCi/L
Christian County34 mi7236.1%3.2 pCi/L
Hopkins County36 mi429.5%1.7 pCi/L
Todd County52 mi6217.7%1.8 pCi/L
Henderson County60 mi5424.1%2.3 pCi/L
Logan County68 mi7931.6%2.4 pCi/L
Daviess County74 mi14520.0%1.8 pCi/L
Lyon County ten-year laboratory totals, against Kentucky's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestKentucky, pooledChange from the row before
2008 to 20171435.7%2.5 pCi/L9.2 pCi/L43.7%Level
2007 to 20161435.7%2.5 pCi/L9.2 pCi/L45.1%+9.0 points
2006 to 20151526.7%2.5 pCi/L14.0 pCi/L46.4%−6.6 points
2005 to 20141233.3%2.6 pCi/L14.0 pCi/L47.3%First on file

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

Lyon County, Geology

The ground under Lyon County

Predicted

USGS's geologic map puts all of Lyon County's mapped land in one class: moderate radon potential. All of it lies in the area the map calls Mississippian Plateau, to which USGS gives a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Lyon County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Mississippian PlateauMississippian marine limestones, dolomites, marine sandstones, siltstones, and shales.Moderate11100%

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

Lyon County beside the ground around it

Across Kentucky 18.2% of the land is rated high; none of Lyon County's is. Of the 5 counties that border it, none has as large a share of moderate-potential ground; Crittenden County comes nearest at 100%.

Share of land by USGS radon potential: Lyon County, the 5 counties bordering it and Kentucky
AreaEPA zoneLow potentialModerate potentialHigh potential
Lyon CountyZone 2None100%None
Caldwell CountyZone 2None100%None
Marshall CountyZone 368.5%31.5%None
Trigg CountyZone 2None100%None
Livingston CountyZone 21.5%98.5%None
Crittenden CountyZone 2None100%None
Kentucky120 counties, pooled by land areaVaries5.7%76.1%18.2%

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

Local help

Lyon County, Local resources

Radon testing and mitigation in Lyon County

What Kentucky's program says
Phone
502-782-2782
Email
Radon@ky.gov

What it means

Lyon County, Questions

Questions about radon in Lyon County

Are radon levels high in Lyon County?

Over the 2008 to 2017 laboratory totals, 35.7% of the radon tests reported to CDC for Lyon County, Kentucky were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of the counties bordering it, 2 have a figure over the 2008 to 2017 laboratory totals: Trigg County reported the largest share at or above 4 pCi/L, 22.2%, and Marshall County the smallest, 10.6%.

Which counties border Lyon County?

Lyon County borders 5 counties: Caldwell County, Marshall County, Trigg County, Livingston County and Crittenden County.

Products

Lyon County, Products

Testing a home in Lyon County

No CDC figure names Lyon County; the nearest county with one, Marshall County (17 miles away), reported 10.6% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, the only reading nearby until a test of this home. In Zone 2 a short-term kit (2 to 90 days) is the quick first check in Lyon County; a long-term test tells the year-round average.

Test kits and monitors3

See every kit and monitor

Best radon monitors for Lyon County homes, compared

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Lyon County, Bordering counties

Counties bordering Lyon County

Calculated by Radon411

Lyon County, Cities and towns

Cities and towns in Lyon County

Lyon County is growing: the Census Bureau puts it at 9,123 residents on July 1, 2025, up 5.2% from 8,673 in 2020. That works out to 43 people per square mile of land. Its largest town, Eddyville, has 2,306 residents, 25.3% of the total. Together its 2 incorporated places hold 32.5% of those residents; the other 67.5% live outside any of them. Reported testing is thin here: 15 tests over 2006 to 2015, or 1.6 for every 1,000 residents (2025 estimate), where Kentucky as a whole comes to 5.0.

From Eddyville to Kuttawa, CDC publishes no figure by town: each reads Lyon County's.

The cities and towns in Lyon County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Eddyville2,306−3.2%25.3%
Kuttawa663+7.6%7.3%

2 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).

Lyon County, Homes

Homes in Lyon County

Of Lyon County's 4,806 homes, 73% are detached houses, against 68% across Kentucky; 17% are mobile homes. Half of its homes were built before 1988, close to Kentucky's 1982: 11% date from before 1960 and 21% from 2000 or later. Owners live in 82% of the occupied homes (Kentucky: 68%), so for most households a test and a fix are their own to order.

Homes in Lyon County, Kentucky, 2019 to 2023
HomesLyon CountyKentucky
Housing units4,8062,010,655
Detached houses73%68%
In buildings of 5 or more4%12%
Mobile homes17%11%
Built before 196011%22%
Built since 200021%24%
Middle year built19881982
Owner-occupied82%68%

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