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 Powder River County, Montana
EPA puts Powder River County in Zone 1, its highest radon zone, and only 8 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
70.3%
Sheridan County
- Sheridan
- 70.3%
- Campbell
- 43.8%
3 of 7 neighbours have 30+ tests, 2006 to 2015
Nearest county
43.1%
Yellowstone County, 133 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
- Powder River
- 100.0%
- Montana
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
8
Too few for a share
- Powder River
- 8
- Needed
- 30
2008 to 2017, 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 Powder River 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
Powder River County, At a glance
Powder River County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Powder River County in
USGS geologic potential: High across 84% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Powder River County, 2008 to 2017, laboratory
CDC holds 8 reported tests for Powder River County over the 2008 to 2017 laboratory totals, with a median of 4.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Powder River County beside the counties around it is how this page reads it.
What these figures count
Only 8 tests were reported to CDC for Powder River 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).
Powder River County, Compared
Powder River County radon figures, compared
Calculated by Radon411CDC's largest figure for Powder River County rests on 8 tests over the 2008 to 2017 laboratory totals, 5 of them at or above 4 pCi/L, so each test moves its share by 12.5 points and no rank or comparison is drawn from it. Results reached as high as 10.0 pCi/L, with a middle value of 4.5 pCi/L.
Of the counties bordering it, 3 have a figure over the 2006 to 2015 laboratory totals: Sheridan County, WY reported the largest share at or above 4 pCi/L, 70.3%, and Campbell County, WY the smallest, 43.8%, with Crook County, WY at 57.1% between. Farther out, Yellowstone County (133 miles away) at 43.1%, Dawson County (134 miles away) at 47.3% and Carbon County (166 miles away) at 52.5% 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 Powder River County in Zone 1, the map's highest label: a predicted county average above 4 pCi/L. USGS geology rates 84% of the county's land high radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Powder River County, Geology
The ground under Powder River County
PredictedMost of the ground under Powder River County is one class on USGS's geologic map: 83.6% of its land is high radon potential, with 16.4% moderate. The map puts 83.4% of Powder River County in the area it calls Great Plains and 16.4% in Eastern Great Plains. USGS gives the first a radon index of 12, in the high band (12 to 17), and the second 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Great Plains | Tertiary sandstone, siltstone, shale, coal. | High | 12 | 83.4% |
| Eastern Great Plains | Cretaceous marine shale and marine and nearshore sandstone, siltstone. | Moderate | 11 | 16.4% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Powder River County beside the ground around it
On high-potential ground Powder River County is close to Montana as a whole: 83.6% of its land against 78.5%. Of the 7 counties that border it, 3 have more high-potential ground, Sheridan County, WY the most at 98.1%.
The map rates the ground, not the air in any home.
Local help
Powder River County, Local resources
Radon testing and mitigation in Powder River 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
Powder River County, Questions
Questions about radon in Powder River County
Are radon levels high in Powder River County?
Over the 2008 to 2017 laboratory totals, 62.5% of the radon tests reported to CDC for Powder River County, Montana were at or above 4 pCi/L, and the median reported pre-mitigation result was 4.5 pCi/L. Of the counties bordering it, 3 have a figure over the 2006 to 2015 laboratory totals: Sheridan County, WY reported the largest share at or above 4 pCi/L, 70.3%, and Campbell County, WY the smallest, 43.8%, with Crook County, WY at 57.1% between.
Which counties border Powder River County?
Powder River County borders 7 counties: Carter County, MT, Rosebud County, MT, Custer County, MT, Crook County, WY, Sheridan County, WY, Campbell County, WY and Big Horn County, MT.
Products
Powder River County, Products
Testing a home in Powder River County
No CDC figure names Powder River County; the nearest county with one, Yellowstone County (133 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 1 the year-round level in Powder River 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
MonitorAEGTEST
HOUND-3699 radon monitor with a 2.1-inch touchscreen
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
First reading: Within 1 hour
Short-term kitempowerDX
Standard Radon Test short-term mail-in radon test kit
- Lab fee included
Method: Passive sampler
In home: 48 to 96 hours
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Powder River County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Powder River County
Explore
Powder River County, Bordering counties
Counties bordering Powder River County
Calculated by Radon411- Radon levels in Sheridan County, WYEPA zone 1
70.3%at or above 4 pCi/L
Median 5.9 pCi/L · 852 tests
- Radon levels in Crook County, WYEPA zone 1
57.1%at or above 4 pCi/L
Median 4.4 pCi/L · 42 tests
- Radon levels in Rosebud County, MTEPA zone 1
50.0%at or above 4 pCi/L
Median 4.4 pCi/L · 6 tests
- Radon levels in Campbell County, WYEPA zone 1
43.8%at or above 4 pCi/L
Median 3.6 pCi/L · 242 tests
- Radon levels in Custer County, MTEPA zone 1
37.9%at or above 4 pCi/L
Median 3.4 pCi/L · 29 tests
- Radon levels in Big Horn County, MTEPA zone 1
25.0%at or above 4 pCi/L
Median 1.9 pCi/L · 20 tests
- Radon levels in Carter County, MTEPA zone 1
No CDC figure for 2006 to 2015; its page reads it against its own neighbours.
Powder River County, Cities and towns
Cities and towns in Powder River County
Powder River County is growing: the Census Bureau puts it at 1,781 residents on July 1, 2025, up 5.1% from 1,694 in 2020. Spread over its land, that is 0.5 people to the square mile. Broadus, its one incorporated place, has 477 residents, 26.8% of the total. Reported testing is thin here: 8 tests over 2008 to 2017, or 4.5 for every 1,000 residents (2025 estimate), where Montana as a whole comes to 8.6.
Broadus is the one incorporated place here; CDC publishes no figure by town, so it reads Powder River County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Broadus | 477 | +4.6% | 26.8% |
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).
Powder River County, Homes
Homes in Powder River County
Powder River County is a place of houses on their own lots: 75% of its 997 homes are detached single-family houses, against 69% across Montana. Half of its homes were built before 1977, close to Montana's 1980: 24% date from before 1960 and 16% from 2000 or later. Owners live in 78% of the occupied homes (Montana: 69%), so for most households a test and a fix are their own to order.
| Homes | Powder River County | Montana |
|---|---|---|
| Housing units | 997 | 522,939 |
| Detached houses | 75% | 69% |
| In buildings of 5 or more | 1% | 9% |
| Mobile homes | 21% | 10% |
| Built before 1960 | 24% | 26% |
| Built since 2000 | 16% | 27% |
| Middle year built | 1977 | 1980 |
| Owner-occupied | 78% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.