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Radon Levels in Laramie County, Wyoming

EPA puts Laramie County in Zone 1, its highest radon zone, and 25.5% of its 1,834 reported radon tests (2008 to 2017, laboratory totals) were at or above 4 pCi/L. Homes with elevated levels occur in all three zones, so only a test measures yours.

Data checked By Radon411Methodology

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  • Share at 4+ pCi/L

    25.5%

    18.8 pts below WY

    Laramie
    25.5%
    Wyoming
    44.3%

    1,834 tests, 2008 to 2017

  • Median result

    2.5pCi/L

    Below action level

    Laramie
    2.5 pCi/L
    EPA
    4.0 pCi/L

    Midpoint of the tests, 2008 to 2017

  • Tests reported

    1,834

    Most tested in Wyoming

    Laramie
    1,834

    Reported to CDC before any fix, 2008 to 2017

  • EPA radon zone

    Zone 1

    Highest potential

    1. Zone 1
    2. 2
    3. 3

    1 highest, 3 lowest

    EPA predicts over 4 pCi/L indoors

  • Rank in Wyoming

    21 of 22

    Lowest quarter

    Laramie
    25.5%
    Sheridan
    69.5%

    By share, of 22 with 30+ tests

Read a result for Laramie County

Starts at Laramie County's median, 2.5 pCi/L

2.5pCi/L

EPA’s own thresholds; the figures are the area’s, never this home’s.

EPA’s reading of 2.5 pCi/L

Between 2 and 4 pCi/L

  1. Under 20 to 1.9 pCi/L
  2. 2 to 4consider a fix
  3. 4 and aboveEPA says fix it

This result is between 2 and 4 pCi/L. EPA recommends considering a fix when the level is between 2 and 4 pCi/L. Laramie County's median reported result, 2008 to 2017.

Interpret this readingWhat a fix costs

The data

Laramie County, At a glance

Laramie County at a glance

Predicted: EPA radon zone

EPA Zone 1: highest predicted potential

EPA puts all of Laramie County in and predicts an average indoor of greater than 4 pCi/L (greater than 150 Bq/m³) across the county. That is one forecast for the whole county, not a reading of any address in it; homes above EPA's turn up in all three zones.

USGS geologic potential: Moderate across 94% of the county's area

Predicted: EPA Map of Radon Zones

Measured: tests reported to CDC

Radon tests reported for Laramie County, 2008 to 2017, laboratory

Reported results by concentration band, Laramie County, 2008 to 2017, laboratory
Under 2 pCi/L: 37%2 to 4 pCi/L: 38%4 pCi/L and above: 25%

Of 1,834 pre-mitigation tests reported to CDC, not homes in this area.

Reported results by concentration band, Laramie County, 2008 to 2017, laboratory: data table
Result bandTests MeasuredShare Measured
Under 2 pCi/L67536.8%
2 to 4 pCi/L69137.7%
4 pCi/L and above46825.5%
What these figures count

These are the 1,834 tests reported to CDC for Laramie County over 2008 to 2017 (laboratory totals), many from homes being sold or already suspected of a problem: they describe the county's reported tests, not this house.

Measured: CDC tracking data. Figure above: 2008 to 2017, laboratory. Measured data period: 2005 to 2017 (every CDC figure on file).

How to read these figures

Laramie County, Compared

Laramie County radon figures, compared

Calculated by Radon411

Laramie County's 1,834 reported tests over the 2008 to 2017 laboratory totals had a middle value of 2.5 pCi/L and a maximum of 180.9 pCi/L, and 25.5% reached 4 pCi/L. Wyoming as a whole (23 Wyoming counties, pooled) comes to 44.3%: 18.8 points higher than here.

Among its state's counties it ranks 21st of 22 Wyoming counties with 30 or more tests for the same period. Statewide for the same period, Sheridan County reported the highest share (69.5%) and Uinta County the lowest (24.6%).

Below the action level, 675 tests (36.8%) came in under 2 pCi/L, against 25.5% statewide, and 691 tests (37.7%) fell between 2 and 4, against 30.2% statewide. CDC's ten-year totals for Laramie County went from 1,784 tests (2005 to 2014) to 1,834 (2008 to 2017), the share going from 25.6% to 25.5%.

EPA's 1993 zone map puts Laramie County in Zone 1, a predicted county average above 4 pCi/L. USGS geology rates 94% of the county's land moderate radon potential.

Next door, the shares run from 26.5% in Platte County to 57.9% in Larimer County, CO.

CDC also counts 57 tests taken after mitigation in Laramie County for the same period: tests in homes where a fix was already in.

Laramie County against Wyoming, the United States and nearby counties, 2008 to 2017, laboratory
AreaTestsAt or above 4 pCi/LMedianDifference from Laramie County
Laramie County1,83425.5%2.5 pCi/LThis county
Wyoming, pooled23 counties, pooled7,63844.3%Not pooled+18.8 points
United States, pooled2,661 counties, pooled2,013,54435.7%Not pooled+10.2 points
Sheridan Countyhighest in the state84669.5%5.8 pCi/L+44.0 points
Uinta Countylowest in the state19924.6%2.2 pCi/L−0.9 points
Larimer County, COborders it9,32557.9%5.0 pCi/L+32.4 points
Weld County, COborders it4,37849.7%3.9 pCi/L+24.2 points
Kimball County, NEborders it8144.4%3.6 pCi/L+18.9 points
Goshen County, WYborders it16841.7%3.3 pCi/L+16.2 points
Albany County, WYborders it39427.9%2.7 pCi/L+2.4 points
Platte County, WYborders it13226.5%2.4 pCi/L+1.0 points
Banner County, NEborders it40.0%2.8 pCi/L−25.5 points
Where Laramie County's reported results fell, 2008 to 2017, laboratory, beside Wyoming and the United States
ResultLaramie County testsLaramie County shareWyoming shareU.S. shareAgainst Wyoming
Under 2 pCi/L67536.8%25.5%39.6%+11.3 points
2 to 4 pCi/L69137.7%30.2%24.7%+7.5 points
4 pCi/L and above46825.5%44.3%35.7%−18.8 points
Laramie County ranked among the 22 Wyoming counties with 30 or more tests, by share at or above 4 pCi/L, 2008 to 2017, laboratory
CountyRankTestsAt or above 4 pCi/LMedian
Campbell County12 of 2227143.9%3.5 pCi/L
Park County13 of 2250542.8%3.4 pCi/L
Big Horn County14 of 229942.4%3.5 pCi/L
Goshen County15 of 2216841.7%3.3 pCi/L
Carbon County16 of 228041.3%3.0 pCi/L
Washakie County17 of 2213038.5%3.2 pCi/L
Johnson County18 of 2213534.8%3.1 pCi/L
Albany County19 of 2239427.9%2.7 pCi/L
Platte County20 of 2213226.5%2.4 pCi/L
Laramie County21 of 221,83425.5%2.5 pCi/L
Uinta County22 of 2219924.6%2.2 pCi/L
Laramie County ten-year laboratory totals, against Wyoming's pooled share
PeriodTestsAt or above 4 pCi/LMedianHighestWyoming, pooledChange from the row before
2008 to 20171,83425.5%2.5 pCi/L180.9 pCi/L44.3%−0.8 points
2007 to 20161,87426.3%2.5 pCi/L180.9 pCi/L44.6%+0.2 points
2006 to 20151,79826.1%2.5 pCi/L155.5 pCi/L45.3%+0.5 points
2005 to 20141,78425.6%2.5 pCi/L155.5 pCi/L45.5%First on file

Pooled shares: Radon411's sum of CDC's county counts for one period.

Laramie County, Geology

The ground under Laramie County

Predicted

Most of the ground under Laramie County is one class on USGS's geologic map: 93.8% of its land is moderate radon potential, with 6.2% high. The map puts 78.3% of Laramie County in the area it calls Tertiary Rocks and 15.5% in White River Formation, with one smaller area beside them. USGS gives both a radon index of 11, in the moderate band (9 to 11).

USGS's geologic areas under Laramie County
AreaThe rock, in USGS's wordsPotentialRadon indexShare of land
Tertiary RocksTertiary sandstone, siltstone, and volcanic ash.Moderate1178.3%
White River FormationSiltstone, sandstone, conglomerate, volcanic tuff.Moderate1115.5%
Laramie MountainsPrecambrian anorthosite, monzonite, gneissic granite, and granite.High126.2%

Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.

Laramie County beside the ground around it

Wyoming as a whole has more high-potential ground than Laramie County: 72.4% of its land, against 6.2% here. Of the 7 counties that border it, 4 have more high-potential ground, Albany County the most at 99.7%.

Share of land by USGS radon potential: Laramie County, the 7 counties bordering it and Wyoming
AreaEPA zoneLow potentialModerate potentialHigh potential
Laramie CountyZone 1None93.8%6.2%
Kimball County, NEZone 2None100%None
Banner County, NEZone 2None100%None
Weld County, COZone 1None33.9%66.2%
Larimer County, COZone 1None1.6%98.4%
Albany CountyZone 1None0.3%99.7%
Platte CountyZone 2None69.9%30.1%
Goshen CountyZone 1None95.3%4.7%
Wyoming23 counties, pooled by land areaVariesNone27.6%72.4%

The map rates the ground, not the air in any home.

Local help

Laramie County, Local resources

Radon testing and mitigation in Laramie County

Listed radon businesses with an address in Laramie County:

Listed radon professionals by town: Cheyenne

What it means

Laramie County, Questions

Questions about radon in Laramie County

Are radon levels high in Laramie County?

Over the 2008 to 2017 laboratory totals, 25.5% of the radon tests reported to CDC for Laramie County, Wyoming were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.5 pCi/L. Of 22 Wyoming counties with 30 or more tests for the same period, 20 reported a higher share; pooled, the state comes to 44.3%.

Which counties border Laramie County?

Laramie County borders 7 counties: Kimball County, NE, Banner County, NE, Weld County, CO, Larimer County, CO, Albany County, WY, Platte County, WY and Goshen County, WY.

Products

Laramie County, Products

Testing a home in Laramie County

In Laramie County, 25.5% of 1,834 tests reported to CDC over the 2008 to 2017 laboratory totals reached 4 pCi/L, against 44.3% pooled across Wyoming. In Zone 1 the year-round level in Laramie 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

Laramie County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Laramie County

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Laramie County, Bordering counties

Counties bordering Laramie County

Calculated by Radon411

Laramie County, Cities and towns

Cities and towns in Laramie County

The Census Bureau estimates 102,938 residents in Laramie County for July 1, 2025, 2,211 more than in 2020 (+2.2%). That works out to 38 people per square mile of land. Cheyenne alone is home to 66,507 of them, 64.6% of the total. Together its 4 incorporated places hold 66.2% of those residents; the other 33.8% live outside any of them. CDC's 1,834 reported tests for 2008 to 2017 work out to 17.8 per 1,000 residents (2025 estimate), close to Wyoming's 13.0.

From Cheyenne to Albin, CDC publishes no figure by town: each reads Laramie County's.

The cities and towns in Laramie County by residents, July 1, 2025
PlaceResidentsSince 2020Share of residents
Cheyenne66,507+1.6%64.6%
Pine Bluffs1,111−4.3%1.1%
Burns399+13.0%0.4%
Albin161−4.7%0.2%

4 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).

Laramie County, Homes

Homes in Laramie County

Of Laramie County's 45,032 homes, 66% are detached houses, against 68% across Wyoming; 8% are in buildings of five or more homes. Half of its homes were built before 1980, close to Wyoming's 1980: 24% date from before 1960 and 27% from 2000 or later. 71% 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 in Laramie County, Wyoming, 2019 to 2023
HomesLaramie CountyWyoming
Housing units45,032275,131
Detached houses66%68%
In buildings of 5 or more8%9%
Mobile homes8%12%
Built before 196024%24%
Built since 200027%24%
Middle year built19801980
Owner-occupied71%72%

Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.