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 Niobrara County, Wyoming
EPA puts Niobrara County in Zone 1, its highest radon zone, and only 12 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
65.7%
Custer County
- Custer
- 65.7%
- Platte
- 26.5%
5 of 7 neighbours have 30+ tests, 2008 to 2017
Nearest county
62.3%
Converse County, 53 miles
- Converse
- 62.3%
- Wyoming
- 44.3%
Share at 4+ pCi/L, 130 tests, 2008 to 2017
Ground above low
100.0%
Level with Wyoming
- Niobrara
- 100.0%
- Wyoming
- 100.0%
Share of land USGS rates moderate or high potential
Tests reported
12
Too few for a share
- Niobrara
- 12
- 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 Niobrara 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
Niobrara County, At a glance
Niobrara County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Niobrara County in
USGS geologic potential: Moderate across 69% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Niobrara County, 2008 to 2017, laboratory
CDC holds 12 reported tests for Niobrara County over the 2008 to 2017 laboratory totals, with a median of 3.5 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Niobrara County beside the counties around it is how this page reads it.
What these figures count
Only 12 tests were reported to CDC for Niobrara 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).
Niobrara County, Compared
Niobrara County radon figures, compared
Calculated by Radon411CDC's largest figure for Niobrara County rests on 12 tests over the 2008 to 2017 laboratory totals, 3 of them at or above 4 pCi/L, so each test moves its share by 8.3 points and no rank or comparison is drawn from it. Results reached as high as 7.9 pCi/L, with a middle value of 3.5 pCi/L.
Of the counties bordering it, 5 have a figure over the 2008 to 2017 laboratory totals: Custer County, SD reported the largest share at or above 4 pCi/L, 65.7%, and Platte County the smallest, 26.5%, with Weston County at 65.6%, Converse County at 62.3% and Goshen County at 41.7% between. Farther out, Campbell County (98 miles away) at 43.9%, Crook County (106 miles away) at 58.8% and Albany County (116 miles away) at 27.9% have figures too. Pooled across 23 Wyoming counties, 44.3% of reported tests reached that level; across every county in the country with a figure, 35.7%.
Statewide for the same period, Sheridan County reported the highest share (69.5%) and Uinta County the lowest (24.6%). EPA's 1993 map puts Niobrara County in Zone 1, the map's highest label: a predicted county average above 4 pCi/L. USGS geology rates 69% of the county's land moderate radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Niobrara County, Geology
The ground under Niobrara County
PredictedUSGS's geologic map splits Niobrara County: 69.5% of its land is moderate radon potential and 30.5% high. The map puts 39.2% of Niobrara County in the area it calls East Powder River Basin and 30.3% in Tertiary Rocks, with 3 smaller areas beside them. USGS gives both a radon index of 11, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| East Powder River Basin | Upper Cretaceous marine sedimentary rocks. | Moderate | 11 | 39.2% |
| Tertiary Rocks | Tertiary sandstone, siltstone, and volcanic ash. | Moderate | 11 | 30.3% |
| Hartville Uplift | Precambrian granite and metasedimentary rocks. | High | 12 | 13.8% |
| Powder River Basin | Cretaceous and Tertiary uranium-bearing marginal-marine and fluvial sandstones. | High | 12 | 13.7% |
| Black Hills | Late Paleozoic sedimentary or Precambrian intrusive igneous rocks. | High | 12 | 3.0% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Niobrara County beside the ground around it
Wyoming as a whole has more high-potential ground than Niobrara County: 72.4% of its land, against 30.5% here. Of the 7 counties that border it, 3 have more high-potential ground, Converse County the most at 87.5%.
The map rates the ground, not the air in any home.
Local help
Niobrara County, Local resources
Radon testing and mitigation in Niobrara County
- Wyoming Radon ProgramWyoming Radon Program, run by Wyoming Department of Health, answers questions about testing, mitigation and the rules in Wyoming.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsAsk the program whether it has free or discounted kits, or compare kits you can buy.
- Compare kits
- Professionals in Wyoming2 professionals are listed in Wyoming.
What it means
Niobrara County, Questions
Questions about radon in Niobrara County
Are radon levels high in Niobrara County?
Over the 2008 to 2017 laboratory totals, 25.0% of the radon tests reported to CDC for Niobrara County, Wyoming were at or above 4 pCi/L, and the median reported pre-mitigation result was 3.5 pCi/L. Of the counties bordering it, 5 have a figure over the 2008 to 2017 laboratory totals: Custer County, SD reported the largest share at or above 4 pCi/L, 65.7%, and Platte County the smallest, 26.5%, with Weston County at 65.6%, Converse County at 62.3% and Goshen County at 41.7% between.
Which counties border Niobrara County?
Niobrara County borders 7 counties: Weston County, WY, Fall River County, SD, Converse County, WY, Sioux County, NE, Goshen County, WY, Custer County, SD and Platte County, WY.
Products
Niobrara County, Products
Testing a home in Niobrara County
No CDC figure names Niobrara County; the nearest county with one, Converse County (53 miles away), reported 62.3% of its tests at or above 4 pCi/L over the 2008 to 2017 laboratory totals, the only reading nearby until a test of this home. In Zone 1 the year-round level in Niobrara 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
RadonScan-Plus USB-powered radon monitor with Wi-Fi
- C-NRPP 2024/25: Not included
- Plug-in
- Wi-Fi
- Alarm
- Screen, app
First reading: Within 5 minutes
Short-term kit
RA100 short-term liquid scintillation radon test kit
- Lab fee extra
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
Niobrara County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Niobrara County
Explore
Niobrara County, Bordering counties
Counties bordering Niobrara County
Calculated by Radon411- Radon levels in Custer County, SDEPA zone 2
65.7%at or above 4 pCi/L
Median 6.2 pCi/L · 108 tests
- Radon levels in Weston County, WYEPA zone 2
65.6%at or above 4 pCi/L
Median 6.3 pCi/L · 32 tests
- Radon levels in Fall River County, SDEPA zone 2
62.5%at or above 4 pCi/L
Median 5.8 pCi/L · 24 tests
- Radon levels in Converse County, WYEPA zone 1
62.3%at or above 4 pCi/L
Median 4.8 pCi/L · 130 tests
- Radon levels in Goshen County, WYEPA zone 1
41.7%at or above 4 pCi/L
Median 3.3 pCi/L · 168 tests
- Radon levels in Sioux County, NEEPA zone 2
31.6%at or above 4 pCi/L
Median 1.9 pCi/L · 19 tests
- Radon levels in Platte County, WYEPA zone 2
26.5%at or above 4 pCi/L
Median 2.4 pCi/L · 132 tests
Niobrara County, Cities and towns
Cities and towns in Niobrara County
About 2,341 people live in Niobrara County by the Census Bureau's estimate for July 1, 2025, 110 fewer than in 2020 (−4.5%). Spread over its land, that is 0.9 people to the square mile. Lusk alone is home to 1,421 of them, 60.7% of the total. Together its 3 incorporated places hold 65.6% of those residents; the other 34.4% live outside any of them. Reported testing is thin here: 12 tests over 2008 to 2017, or 5.1 for every 1,000 residents (2025 estimate), where Wyoming as a whole comes to 13.0.
From Lusk to Van Tassell, CDC publishes no figure by town: each reads Niobrara County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Lusk | 1,421 | −6.9% | 60.7% |
| Manville | 91 | −1.1% | 3.9% |
| Van Tassell | 24 | Level | 1.0% |
3 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).
Niobrara County, Homes
Homes in Niobrara County
Niobrara County is a place of houses on their own lots: 75% of its 1,378 homes are detached single-family houses, against 68% across Wyoming. The homes are older than Wyoming's as a whole: half were built before 1955 (1980 for Wyoming), and 54% date from before 1960. 65% of occupied homes are lived in by their owner (Wyoming: 72%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Niobrara County | Wyoming |
|---|---|---|
| Housing units | 1,378 | 275,131 |
| Detached houses | 75% | 68% |
| In buildings of 5 or more | 8% | 9% |
| Mobile homes | 13% | 12% |
| Built before 1960 | 54% | 24% |
| Built since 2000 | 9% | 24% |
| Middle year built | 1955 | 1980 |
| Owner-occupied | 65% | 72% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.