Long-term kit
RL116 long-term radon test kit
- Lab fee extra
Method: Alpha track
In home: 90 days to 12 months
Locations and reports
Radon Levels in McCone County, Montana
EPA puts McCone County in Zone 1, its highest radon zone, and only 1 radon test from it is 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
Highest bordering
75.0%
Richland County
- Richland
- 75.0%
- Dawson
- 47.3%
3 of 6 neighbours have 30+ tests, 2006 to 2015
Nearest county
47.3%
Dawson County, 49 miles
- Dawson
- 47.3%
- Montana
- 47.4%
Share at 4+ pCi/L, 55 tests, 2006 to 2015
Ground above low
100.0%
Level with Montana
- McCone
- 100.0%
- Montana
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
6
Too few for a share
- McCone
- 6
- Needed
- 30
2005 to 2014, laboratory
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Read a result for McCone County
Starts at EPA's action level
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
- 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.
The data
McCone County, At a glance
McCone County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of McCone 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 McCone County, 2008 to 2017, laboratory
CDC holds 1 reported test for McCone County over the 2008 to 2017 laboratory totals, a result of 1.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). McCone County beside the counties around it is how this page reads it.
What these figures count
Only 1 test was reported to CDC for McCone 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).
McCone County, Compared
McCone County radon figures, compared
Calculated by Radon411CDC's largest figure for McCone County rests on 6 tests over the 2005 to 2014 laboratory totals, 2 of them at or above 4 pCi/L, so each test moves its share by 16.7 points and no rank or comparison is drawn from it. Results reached as high as 14.7 pCi/L, with a middle value of 2.5 pCi/L.
Of the counties bordering it, 3 have a figure over the 2006 to 2015 laboratory totals: Richland County reported the largest share at or above 4 pCi/L, 75.0%, and Dawson County the smallest, 47.3%, with Valley County at 50.0% between. Farther out, Sheridan County (95 miles away) at 75.7%, Fergus County (163 miles away) at 72.2% and Yellowstone County (167 miles away) at 43.1% have figures too. Pooled across 52 Montana counties, 47.4% of reported tests reached that level; across every county in the country with a figure, 36.3%.
Statewide for the same period, Sheridan County reported the highest share (75.7%) and Hill County the lowest (35.0%). EPA's 1993 map puts McCone County in Zone 1, the map's highest label: a predicted county average above 4 pCi/L. USGS geology rates 100% of the county's land high radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
McCone County, Geology
The ground under McCone County
PredictedUSGS's geologic map puts all of McCone County's mapped land in one class: high radon potential. The map puts 51.3% of McCone County in the area it calls Great Plains (Glaciated) and 48.7% in Great Plains. USGS gives the first a radon index of 13 and the second 12, both in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Great Plains (Glaciated) | Glacial deposits derived from Cretaceous shales containing higher than average amounts of uranium. | High | 13 | 51.3% |
| Great Plains | Tertiary sandstone, siltstone, shale, coal. | High | 12 | 48.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
McCone County beside the ground around it
McCone County has more high-potential ground than Montana as a whole: 100% of its land against 78.5%. Of the 6 counties that border it, none has as large a share of high-potential ground; Richland County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
McCone County, Local resources
Radon testing and mitigation in McCone County
- Radon Control ProgramRadon Control Program, run by Montana DEQ, does not license radon professionals and offers free or discounted test kits, and answers questions about testing and mitigation in Montana.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
Energy Bureau staff manage the radon information toll-free hotline and distribute subsidized radon test kits to Montana residents.
- Compare kits
- See the Montana directoryNo professionals are listed in Montana yet. The state program can point you to registered testers and mitigators.
What Montana's program says
- Phone
- 1-800-546-0483
- Licensing of radon professionals
Montana DEQ does not certify or require proof of certification for the contractors listed.
What it means
McCone County, Questions
Questions about radon in McCone County
Are radon levels high in McCone County?
Over the 2008 to 2017 laboratory totals, 0.0% of the radon tests reported to CDC for McCone County, Montana were at or above 4 pCi/L, and the median reported pre-mitigation result was 1.5 pCi/L. Of the counties bordering it, 3 have a figure over the 2006 to 2015 laboratory totals: Richland County reported the largest share at or above 4 pCi/L, 75.0%, and Dawson County the smallest, 47.3%, with Valley County at 50.0% between.
Which counties border McCone County?
McCone County borders 6 counties: Dawson County, Richland County, Prairie County, Valley County, Roosevelt County and Garfield County.
Products
McCone County, Products
Testing a home in McCone County
No CDC figure names McCone County; the nearest county with one, Dawson County (49 miles away), reported 47.3% of its tests at or above 4 pCi/L over the 2006 to 2015 laboratory totals, the only reading nearby until a test of this home. In Zone 1 the year-round level in McCone 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
Corentium Home battery digital radon detector
- C-NRPP 2024/25: Approved
- Battery
- Screen
Method: Alpha spectrometry
Short-term kit
RA400 short-term liquid scintillation radon test kit, lab fee included
- Lab fee included
Method: Liquid scintillation
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
McCone County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like McCone County
Explore
McCone County, Bordering counties
Counties bordering McCone County
Calculated by Radon411- Radon levels in Roosevelt CountyEPA zone 1
93.8%at or above 4 pCi/L
Median 9.3 pCi/L · 16 tests
- Radon levels in Richland CountyEPA zone 1
75.0%at or above 4 pCi/L
Median 5.6 pCi/L · 40 tests
- Radon levels in Valley CountyEPA zone 1
50.0%at or above 4 pCi/L
Median 4.2 pCi/L · 40 tests
- Radon levels in Dawson CountyEPA zone 1
47.3%at or above 4 pCi/L
Median 3.5 pCi/L · 55 tests
- Radon levels in Prairie CountyEPA zone 1
28.6%at or above 4 pCi/L
Median 3.3 pCi/L · 7 tests
- Radon levels in Garfield CountyEPA zone 1
No CDC figure for 2006 to 2015; its page reads it against its own neighbours.
McCone County, Cities and towns
Cities and towns in McCone County
About 1,720 people live in McCone County by the Census Bureau's estimate for July 1, 2025, 11 fewer than in 2020 (−0.6%). Spread over its land, that is 0.7 people to the square mile. Circle, its one incorporated place, has 590 residents, 34.3% of the total. Reported testing is thin here: 6 tests over 2005 to 2014, or 3.5 for every 1,000 residents (2025 estimate), where Montana as a whole comes to 6.7.
Circle is the one incorporated place here; CDC publishes no figure by town, so it reads McCone County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Circle | 590 | −0.5% | 34.3% |
One incorporated place, 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).
McCone County, Homes
Homes in McCone County
McCone County is a place of houses on their own lots: 79% of its 1,082 homes are detached single-family houses, against 69% across Montana. The homes are older than Montana's as a whole: half were built before 1965 (1980 for Montana), and 41% date from before 1960. Owners live in 86% of the occupied homes (Montana: 69%), so for most households a test and a fix are their own to order.
| Homes | McCone County | Montana |
|---|---|---|
| Housing units | 1,082 | 522,939 |
| Detached houses | 79% | 69% |
| In buildings of 5 or more | 1% | 9% |
| Mobile homes | 16% | 10% |
| Built before 1960 | 41% | 26% |
| Built since 2000 | 15% | 27% |
| Middle year built | 1965 | 1980 |
| Owner-occupied | 86% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.