Long-term kit
RL416 long-term radon test kit, lab fee included
- Lab fee included
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in Holt County, Missouri
EPA puts Holt County in Zone 1, its highest radon zone, and only 1 radon test from it is on file with CDC (2023). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Share at 4+ pCi/L
64.5%
33.7 pts above MO
- Holt
- 64.5%
- Missouri
- 30.8%
31 tests, 2007 to 2016
Median result
5.0pCi/L
Action level reached
- Holt
- 5.0 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2007 to 2016
Tests reported
31
70th of 72 by tests
- Holt
- 31
- St. Louis
- 16,567
Reported to CDC before any fix, 2007 to 2016
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Missouri
2 of 72
Top quarter
- Holt
- 64.5%
- Atchison
- 70.5%
By share, of 72 with 30+ tests
Read a result for Holt County
Starts at Holt County's median, 5.0 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 5.0 pCi/L
At or above 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 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. Holt County's median reported result, 2007 to 2016.
The data
Holt County, At a glance
Holt County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Holt County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Holt County, 2023
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 100.0% |
| 2016 | 50.0% |
| 2017 | 100.0% |
| 2018 | 0.0% |
| 2023 | 100.0% |
2023: 100.0%. Across these years the share ran from 0.0% to 100.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
Only 1 test was reported to CDC for Holt County over 2023, 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: 2023. Measured data period: 2005 to 2023 (every CDC figure on file).
Holt County, Compared
Holt County radon figures, compared
Calculated by Radon411More than half: 64.5% of the 31 radon tests reported to CDC for Holt County over the 2007 to 2016 laboratory totals read at least 4 pCi/L. That places it 2nd of 72 Missouri counties with 30 or more tests for the same period. That is 33.7 points above the 30.8% pooled from 115 Missouri counties.
The newest figure, in 2023, counts only 1 test (100.0% at or above 4 pCi/L), too few to compare, so this reading uses the 31-test figure.
The median result, 5.0 pCi/L, sits above EPA's 4 pCi/L action level, and the top reported result was 14.6 pCi/L. The rest split 9.7% under 2 pCi/L and 25.8% from 2 to 4 (Missouri: 41.2% and 27.9%). Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 64.5% share point the same way here.
3 of its 5 bordering counties with figures ran higher, led by Nemaha County, NE at 76.3%; Nodaway County reported 37.3%. Statewide for the same period, Atchison County reported the highest share (70.5%) and Vernon County the lowest (9.1%).
The busiest year on file was 2014, with 4 tests reported; the quietest, 2023, had 1.
Nationally, every county with a figure for the same period pools to 35.8%; Holt County sits 28.7 points above it.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Holt County, Geology
The ground under Holt County
PredictedUSGS's geologic map puts all of Holt County's mapped land in one class: high radon potential. All of it lies in the area the map calls Northwestern Dissected Till Plains, to which USGS gives a radon index of 13, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Northwestern Dissected Till Plains | Pennsylvanian shales covered by thick loess. | High | 13 | 99.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Holt County beside the ground around it
Holt County has more high-potential ground than Missouri as a whole: 100% of its land against 8.2%. Of the 6 counties that border it, none has as large a share of high-potential ground; Doniphan County, KS comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Holt County, Local resources
Radon testing and mitigation in Holt County
- Missouri Radon ProgramMissouri Radon Program, run by Missouri Department of Health and Senior Services, offers free or discounted test kits, and answers questions about testing and mitigation in Missouri.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Free radon test kits are available for Missouri residents (limit one per household).
- Compare kits
- Professionals in Missouri27 professionals are listed in Missouri.
What Missouri's program says
- Phone
- 573-751-6102
- radon@health.mo.gov
What it means
Holt County, Questions
Questions about radon in Holt County
Are radon levels high in Holt County?
In 2023, 100.0% of the radon tests reported to CDC for Holt County, Missouri were at or above 4 pCi/L, and the median reported pre-mitigation result was 8.2 pCi/L. Of 72 Missouri counties with 30 or more tests for the same period, 1 reported a higher share; pooled, the state comes to 30.8%.
Which counties border Holt County?
Holt County borders 6 counties: Doniphan County, KS, Andrew County, MO, Nodaway County, MO, Richardson County, NE, Atchison County, MO and Nemaha County, NE.
Products
Holt County, Products
Testing a home in Holt County
In Holt County, 64.5% of 31 tests reported to CDC over the 2007 to 2016 laboratory totals reached 4 pCi/L, against 30.8% pooled across Missouri. In Zone 1 the year-round level in Holt 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
Monitor
View Radon Wi-Fi radon monitor with an e-paper display
- C-NRPP 2024/25: Approved
- Battery
- Wi-Fi, Bluetooth
- Screen, app
Method: Alpha spectrometry
Readings: Every 60 minutes
Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Holt County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Holt County
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Holt County, Bordering counties
Counties bordering Holt County
Calculated by Radon411- Radon levels in Nemaha County, NEEPA zone 1
76.3%at or above 4 pCi/L
Median 8.6 pCi/L · 299 tests · 11.8 points above Holt County
- Radon levels in Richardson County, NEEPA zone 1
76.1%at or above 4 pCi/L
Median 7.6 pCi/L · 473 tests · 11.6 points above Holt County
- Radon levels in Atchison County, MOEPA zone 1
70.5%at or above 4 pCi/L
Median 5.5 pCi/L · 88 tests · 6.0 points above Holt County
- Radon levels in Andrew County, MOEPA zone 1
60.4%at or above 4 pCi/L
Median 4.9 pCi/L · 149 tests · 4.1 points below Holt County
- Radon levels in Nodaway County, MOEPA zone 1
37.3%at or above 4 pCi/L
Median 2.8 pCi/L · 193 tests · 27.2 points below Holt County
- Radon levels in Doniphan County, KSEPA zone 2
No CDC figure for 2007 to 2016; its page reads it against its own neighbours.
Holt County, Cities and towns
Cities and towns in Holt County
Holt County's population has barely moved since 2020: 4,200 residents on July 1, 2025 against 4,183 then, by the Census Bureau's estimates. Spread over its land, that is 9.1 people to the square mile. Its largest town, Mound City, has 999 residents, 23.8% of the total. Together its 9 incorporated places hold 60.6% of those residents; the other 39.4% live outside any of them. CDC's 31 reported tests for 2007 to 2016 work out to 7.4 per 1,000 residents (2025 estimate), close to Missouri's 8.8.
From Mound City to Corning, CDC publishes no figure by town: each reads Holt County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Mound City | 999 | +0.5% | 23.8% |
| Oregon | 827 | +0.4% | 19.7% |
| Maitland | 276 | +0.7% | 6.6% |
| Forest City | 245 | Level | 5.8% |
| Craig | 103 | Level | 2.5% |
| Big Lake | 71 | +4.4% | 1.7% |
| Fortescue | 21 | Level | 0.5% |
| Bigelow | 4 | Level | Under 0.1% |
| Corning | 0 | Not published | 0.0% |
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).
Holt County, Homes
Homes in Holt County
Holt County is a place of houses on their own lots: 83% of its 2,420 homes are detached single-family houses, against 70% across Missouri. The homes are older than Missouri's as a whole: half were built before 1968 (1978 for Missouri), and 41% date from before 1960. Owners live in 78% of the occupied homes (Missouri: 68%), so for most households a test and a fix are their own to order.
| Homes | Holt County | Missouri |
|---|---|---|
| Housing units | 2,420 | 2,809,501 |
| Detached houses | 83% | 70% |
| In buildings of 5 or more | 2% | 13% |
| Mobile homes | 9% | 5% |
| Built before 1960 | 41% | 28% |
| Built since 2000 | 16% | 21% |
| Middle year built | 1968 | 1978 |
| Owner-occupied | 78% | 68% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.