Short-term kit
PicoCan short-term charcoal canister radon test
- Lab fee included
Method: Charcoal
In home: 48 to 96 hours
Locations and reports
Radon Levels in Musselshell County, Montana
EPA puts Musselshell County in Zone 2, its middle radon zone, and only 17 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
Highest bordering
72.2%
Fergus County
- Fergus
- 72.2%
- Yellowstone
- 43.1%
2 of 5 neighbours have 30+ tests, 2006 to 2015
Nearest county
43.1%
Yellowstone County, 39 miles
- Yellowstone
- 43.1%
- Montana
- 47.4%
Share at 4+ pCi/L, 1,421 tests, 2006 to 2015
Ground above low
100.0%
Level with Montana
- Musselshell
- 100.0%
- Montana
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
17
Too few for a share
- Musselshell
- 17
- Needed
- 30
2008 to 2017, laboratory
EPA radon zone
Zone 2
Moderate potential
- 1
- Zone 2
- 3
1 highest, 3 lowest
EPA predicts 2 to 4 pCi/L indoors
Read a result for Musselshell 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
Musselshell County, At a glance
Musselshell County at a glance
Predicted: EPA radon zone
EPA Zone 2: moderate predicted potential
Musselshell County is a
USGS geologic potential: Moderate across 99% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Musselshell County, 2008 to 2017, laboratory
CDC holds 17 reported tests for Musselshell County over the 2008 to 2017 laboratory totals, with a median of 2.6 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Musselshell County beside the counties around it is how this page reads it.
What these figures count
Only 17 tests were reported to CDC for Musselshell 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).
Musselshell County, Compared
Musselshell County radon figures, compared
Calculated by Radon411CDC's largest figure for Musselshell County rests on 17 tests over the 2008 to 2017 laboratory totals, 5 of them at or above 4 pCi/L, so each test moves its share by 5.9 points and no rank or comparison is drawn from it. Results reached as high as 12.2 pCi/L, with a middle value of 2.6 pCi/L.
Of the counties bordering it, 2 have a figure over the 2006 to 2015 laboratory totals: Fergus County reported the largest share at or above 4 pCi/L, 72.2%, and Yellowstone County the smallest, 43.1%. Farther out, Stillwater County (75 miles away) at 61.8%, Carbon County (93 miles away) at 52.5% and Judith Basin County (96 miles away) at 64.3% 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 Musselshell County in Zone 2, its middle label: a predicted county average between 2 and 4 pCi/L. USGS geology rates 99% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Musselshell County, Geology
The ground under Musselshell County
PredictedMost of the ground under Musselshell County is one class on USGS's geologic map: 99.4% of its land is moderate radon potential, with 0.6% high. 99.4% of it lies in the area the map calls Plains and Mountains, to which USGS gives a radon index of 10, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Plains and Mountains | Marine and continental shale, siltstone, and sandstone of Cretaceous and Tertiary ages, and volcanic rocks. | Moderate | 10 | 99.4% |
| Northern Rocky Mountains | Granitic, metaigneous, metasedimentary rocks, valley fill colluvium and alluvium. | High | 13 | 0.6% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Musselshell County beside the ground around it
Montana as a whole has more high-potential ground than Musselshell County: 78.5% of its land, against 0.6% here. Of the 5 counties that border it, 4 have more high-potential ground, Fergus County the most at 66.9%.
The map rates the ground, not the air in any home.
Local help
Musselshell County, Local resources
Radon testing and mitigation in Musselshell 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
Musselshell County, Questions
Questions about radon in Musselshell County
Are radon levels high in Musselshell County?
Over the 2008 to 2017 laboratory totals, 29.4% of the radon tests reported to CDC for Musselshell County, Montana were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.6 pCi/L. Of the counties bordering it, 2 have a figure over the 2006 to 2015 laboratory totals: Fergus County reported the largest share at or above 4 pCi/L, 72.2%, and Yellowstone County the smallest, 43.1%.
Which counties border Musselshell County?
Musselshell County borders 5 counties: Yellowstone County, Golden Valley County, Petroleum County, Fergus County and Rosebud County.
Products
Musselshell County, Products
Testing a home in Musselshell County
No CDC figure names Musselshell County; the nearest county with one, Yellowstone County (39 miles away), reported 43.1% 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 2 a short-term kit (2 to 90 days) is the quick first check in Musselshell County; a long-term test tells the year-round average.
Test kits and monitors3
See every kit and monitor
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
MonitorAranet
Radon Plus battery digital radon monitor with an e-ink screen
- C-NRPP 2024/25: Approved
- Battery
- Bluetooth
- Alarm
- Screen, app
Method: Ion chamber
First reading: Within 10 minutes
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Explore
Musselshell County, Bordering counties
Counties bordering Musselshell County
Calculated by Radon411- Radon levels in Golden Valley CountyEPA zone 2
100.0%at or above 4 pCi/L
Median 5.0 pCi/L · 1 test
- Radon levels in Fergus CountyEPA zone 1
72.2%at or above 4 pCi/L
Median 7.0 pCi/L · 72 tests
- Radon levels in Rosebud CountyEPA zone 1
50.0%at or above 4 pCi/L
Median 4.4 pCi/L · 6 tests
- Radon levels in Yellowstone CountyEPA zone 2
43.1%at or above 4 pCi/L
Median 3.5 pCi/L · 1,421 tests
- Radon levels in Petroleum CountyEPA zone 2
No CDC figure for 2006 to 2015; its page reads it against its own neighbours.
Musselshell County, Cities and towns
Cities and towns in Musselshell County
Musselshell County is growing: the Census Bureau puts it at 5,582 residents on July 1, 2025, up 17.6% from 4,748 in 2020. Spread over its land, that is 3.0 people to the square mile. Its largest town, Roundup, has 2,075 residents, 37.2% of the total. Together its 2 incorporated places hold 39.8% of those residents; the other 60.2% live outside any of them. Reported testing is thin here: 17 tests over 2008 to 2017, or 3.0 for every 1,000 residents (2025 estimate), where Montana as a whole comes to 8.6.
From Roundup to Melstone, CDC publishes no figure by town: each reads Musselshell County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Roundup | 2,075 | +18.5% | 37.2% |
| Melstone | 147 | +16.7% | 2.6% |
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).
Musselshell County, Homes
Homes in Musselshell County
Musselshell County is a place of houses on their own lots: 78% of its 2,677 homes are detached single-family houses, against 69% across Montana. Half of its homes were built before 1975, close to Montana's 1980: 36% date from before 1960 and 18% from 2000 or later. Owners live in 83% of the occupied homes (Montana: 69%), so for most households a test and a fix are their own to order.
| Homes | Musselshell County | Montana |
|---|---|---|
| Housing units | 2,677 | 522,939 |
| Detached houses | 78% | 69% |
| In buildings of 5 or more | 1% | 9% |
| Mobile homes | 19% | 10% |
| Built before 1960 | 36% | 26% |
| Built since 2000 | 18% | 27% |
| Middle year built | 1975 | 1980 |
| Owner-occupied | 83% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.