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Radon Levels in Knox County, Nebraska

EPA puts Knox County in Zone 1, its highest radon zone, and high results are common there: 60.9% of the 46 radon tests reported to CDC (2023) 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

    60.9%

    22.7 pts above NE

    Knox
    60.9%
    Nebraska
    38.2%

    46 tests, 2023

  • Median result

    4.7pCi/L

    Action level reached

    Knox
    4.7 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2023

  • Tests reported

    46

    27th of 33 by tests

    Knox
    46
    Lancaster
    4,058

    Reported to CDC before any fix, 2023

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Nebraska

    19 of 33

    Middle half

    Knox
    60.9%
    Gage
    79.8%

    By share, of 33 with 30+ tests

Read a result for Knox County

Starts at Knox County's median, 4.7 pCi/L

4.7pCi/L

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

EPA’s reading of 4.7 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. Knox County's median reported result, 2023.

Interpret this readingWhat a fix costs

The data

Knox County, At a glance

Knox County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Knox County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: High across 80% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Knox County, 2023

Share of reported tests at or above 4 pCi/L, by year, Knox County
Share of reported tests at or above 4 pCi/L, by year, Knox County
YearShare of reported tests at or above 4 pCi/L
201456.2%
201561.9%
201671.2%
201764.5%
201858.3%
201947.8%
202073.5%
202131.1%
202283.3%
202360.9%

2023: 60.9%. Across these years the share ran from 31.1% to 83.3%. Each column counts radon tests reported to CDC that year, not homes.

What these figures count

These are the 46 tests reported to CDC for Knox County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).

How to read these figures

Knox County, Compared

Knox County radon figures, compared

Calculated by Radon411

More than half: 60.9% of the 46 radon tests reported to CDC for Knox County in 2023 read at least 4 pCi/L. That places it 19th of 33 Nebraska counties with 30 or more tests for the same period. That is 22.7 points above the 38.2% pooled from 86 Nebraska counties.

The median result, 4.7 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 21.3 pCi/L. The rest split 6.5% under 2 pCi/L and 32.6% from 2 to 4 (Nebraska: 39.2% and 22.6%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 60.9% share point the same way here.

1 of its 2 bordering counties with figures ran higher, led by Cedar County at 78.0%; Pierce County reported 56.4%. Statewide for the same period, Gage County reported the highest share (79.8%) and Dakota County the lowest (3.1%).

The busiest year on file was 2021, with 366 tests reported; the quietest, 2022, had 30.

Over 10 years of annual figures the share rose 4.7 points, from 56.2% in 2014 to 60.9% in 2023; its peak was 83.3% in 2022. Nationally, every county with a figure for the same period pools to 33.4%; Knox County sits 27.5 points above it. CDC also counts 12 tests taken after mitigation in Knox County for the same period: tests in homes where a fix was already in.

Share of reported tests at or above 4 pCi/L by year, Knox County against Nebraska2014 to 2023, years with 30 or more tests: Knox County 56.2% to 60.9%, the state's pooled share 38.2% in 2023.
Knox CountyNebraska, pooled
Share of reported tests at or above 4 pCi/L by year, Knox County against Nebraska: data table
YearTestsKnox County, at or above 4 pCi/LNebraska, pooled
201426756.2%50.5%
201525261.9%53.3%
201621971.2%47.4%
201727964.5%47.7%
201836058.3%44.5%
201920747.8%44.3%
202014773.5%42.2%
202136631.1%34.9%
20223083.3%34.0%
20234660.9%38.2%
Knox County against Nebraska, the United States and nearby counties, 2023
AreaTestsAt or above 4 pCi/LMedianDifference from Knox County
Knox County4660.9%4.7 pCi/LThis county
Nebraska, pooled86 counties, pooled11,16338.2%Not pooled−22.7 points
United States, pooled642 counties, pooled128,74033.4%Not pooled−27.5 points
Gage Countyhighest in the state8479.8%9.4 pCi/L+18.9 points
Dakota Countylowest in the state1303.1%0.4 pCi/L−57.8 points
Boyd County, NEborders it5100.0%10.0 pCi/L+39.1 points
Cedar County, NEborders it5078.0%6.8 pCi/L+17.1 points
Antelope County, NEborders it2774.1%4.6 pCi/L+13.2 points
Pierce County, NEborders it5556.4%5.0 pCi/L−4.5 points
Holt County, NEborders it616.7%3.5 pCi/L−44.2 points
Where Knox County's reported results fell, 2023, beside Nebraska and the United States
ResultKnox County testsKnox County shareNebraska shareU.S. shareAgainst Nebraska
Under 2 pCi/L36.5%39.2%41.4%−32.7 points
2 to 4 pCi/L1532.6%22.6%25.2%+10.0 points
4 pCi/L and above2860.9%38.2%33.4%+22.7 points
Knox County ranked among the 33 Nebraska counties with 30 or more tests, by share at or above 4 pCi/L, 2023
CountyRankTestsAt or above 4 pCi/LMedian
York County14 of 336264.5%5.7 pCi/L
Otoe County15 of 335964.4%5.7 pCi/L
Red Willow County16 of 335362.3%4.6 pCi/L
Dodge County17 of 3311662.1%5.0 pCi/L
Richardson County18 of 333461.8%5.1 pCi/L
Knox County19 of 334660.9%4.7 pCi/L
Nemaha County20 of 333259.4%5.7 pCi/L
Pierce County21 of 335556.4%5.0 pCi/L
Buffalo County22 of 3317355.5%4.2 pCi/L
Sarpy County23 of 3375551.9%4.1 pCi/L
Douglas County24 of 332,75438.7%2.9 pCi/L
Knox County radon tests by year, against Nebraska's pooled share
YearTestsAt or above 4 pCi/LMedianHighestNebraska, pooledChange from the row before
20234660.9%4.7 pCi/L21.3 pCi/L38.2%−22.4 points
20223083.3%7.0 pCi/L31.0 pCi/L34.0%+52.2 points
202136631.1%2.8 pCi/L25.2 pCi/L34.9%−42.4 points
202014773.5%6.0 pCi/L28.0 pCi/L42.2%+25.7 points
201920747.8%3.8 pCi/L37.0 pCi/L44.3%−10.5 points
201836058.3%5.4 pCi/L44.2 pCi/L44.5%−6.2 points
201727964.5%5.9 pCi/L44.4 pCi/L47.7%−6.7 points
201621971.2%5.2 pCi/L33.2 pCi/L47.4%+9.3 points
201525261.9%5.5 pCi/L55.1 pCi/L53.3%+5.7 points
201426756.2%4.8 pCi/L56.6 pCi/L50.5%First on file

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

Knox County, Geology

The ground under Knox County

Predicted

Most of the ground under Knox County is one class on USGS's geologic map: 80.0% of its land is high radon potential, with 20.0% moderate. The map puts 43.4% of Knox County in the area it calls Pre-Wisconsin glacial deposits and 36.1% in Sharon Springs, with 2 smaller areas beside them. USGS gives the first a radon index of 13 and the second 12, both in the high band (12 to 17).

USGS's geologic areas under Knox County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Pre-Wisconsin glacial depositsLoess-mantled glacial drift.High1343.4%
Sharon SpringsCretaceous Pierre Shale bedrock, including the uranium-bearing Sharon Springs Member.High1236.1%
Pierre ShaleCretaceous marine shaleModerate1120.0%
Missouri Coteau/James River Lowland/Coteau des PrairiesGlacial drift derived largely from Cretaceous marine shale.High140.5%

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

Knox County beside the ground around it

Knox County has more high-potential ground than Nebraska as a whole: 80.0% of its land against 40.9%. Of the 8 counties that border it, 5 have more high-potential ground, Bon Homme County, SD the most at 100%.

Share of land by USGS radon potential: Knox County, the 8 counties bordering it and Nebraska
AreaEPA zoneLow potentialModerate potentialHigh potential
Knox CountyZone 1None20.0%80.0%
Bon Homme County, SDZone 1NoneNone100%
Antelope CountyZone 22.5%81.2%16.3%
Pierce CountyZone 1None43.2%56.8%
Cedar CountyZone 1NoneNone100%
Yankton County, SDZone 1NoneNone100%
Boyd CountyZone 1None4.9%95.1%
Holt CountyZone 355.1%39.7%5.2%
Charles Mix County, SDZone 1None0.2%99.8%
Nebraska93 counties, pooled by land areaVaries28.2%30.9%40.9%

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

Local help

Knox County, Local resources

Radon testing and mitigation in Knox County

Listed radon businesses with an address in Knox County:

Listed radon professionals by town: Niobrara

What Nebraska's program says
Phone
(402) 471-1005
Licensing of radon professionals
If radon testing is done in schools, offices, or other places of work, it must be done by a licensed radon measurement business.

What it means

Knox County, Questions

Questions about radon in Knox County

Are radon levels high in Knox County?

In 2023, 60.9% of the radon tests reported to CDC for Knox County, Nebraska were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.7 pCi/L. Of 33 Nebraska counties with 30 or more tests for the same period, 18 reported a higher share; pooled, the state comes to 38.2%.

Which counties border Knox County?

Knox County borders 8 counties: Bon Homme County, SD, Antelope County, NE, Pierce County, NE, Cedar County, NE, Yankton County, SD, Boyd County, NE, Holt County, NE and Charles Mix County, SD.

Products

Knox County, Products

Testing a home in Knox County

In Knox County, 60.9% of 46 tests reported to CDC in 2023 reached 4 pCi/L, against 38.2% pooled across Nebraska. In Zone 1 the year-round level in Knox County is the one to know: a long-term test (more than 90 days) or a monitor, with a short-term kit for a first answer.

Test kits and monitors3

See every kit and monitor

Knox County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Knox County

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Knox County, Bordering counties

Counties bordering Knox County

Calculated by Radon411

Knox County, Cities and towns

Cities and towns in Knox County

About 8,335 people live in Knox County by the Census Bureau's estimate for July 1, 2025, 42 fewer than in 2020 (−0.5%). Spread over its land, that is 7.5 people to the square mile. No town dominates: Creighton, the largest, has 1,113 residents, 13.4% of the total. Together its 11 incorporated places hold 58.8% of those residents; the other 41.2% live outside any of them. CDC's 46 reported tests for 2023 work out to 5.5 per 1,000 residents (2025 estimate), close to Nebraska's 5.5.

From Creighton to Bazile Mills, CDC publishes no figure by town: each reads Knox County's.

The cities and towns in Knox County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Creighton1,113−3.1%13.4%
Bloomfield941−4.4%11.3%
Crofton761+1.2%9.1%
Wausa579−1.4%6.9%
Verdigre532−2.6%6.4%
Santee429+1.7%5.1%
Niobrara362−0.8%4.3%
Center71−2.7%0.9%
Winnetoon53Level0.6%
Verdel41+2.5%0.5%
Bazile Mills21Level0.3%

11 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).

Knox County, Homes

Homes in Knox County

Knox County is a place of houses on their own lots: 86% of its 4,527 homes are detached single-family houses, against 72% across Nebraska. The homes are older than Nebraska's as a whole: half were built before 1966 (1975 for Nebraska), and 44% date from before 1960. Owners live in 79% of the occupied homes (Nebraska: 67%), so for most households a test and a fix are their own to order.

Homes in Knox County, Nebraska, 2019 to 2023
HomesKnox CountyNebraska
Housing units4,527855,631
Detached houses86%72%
In buildings of 5 or more3%17%
Mobile homes8%3%
Built before 196044%32%
Built since 200013%22%
Middle year built19661975
Owner-occupied79%67%

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