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 Corson County, South Dakota
EPA puts Corson County in Zone 1, its highest radon zone, and only 2 radon tests from it are on file with CDC (2006 to 2015, laboratory totals). Homes with elevated levels occur in all three zones, so only a test measures yours.
Data checked By Radon411Methodology
Highest bordering
69.4%
Emmons County
- Emmons
- 69.4%
1 of 8 neighbours have 30+ tests, 2006 to 2015
Nearest county
61.8%
Edmunds County, 98 miles
- Edmunds
- 61.8%
- SD
- 58.8%
Share at 4+ pCi/L, 68 tests, 2006 to 2015
Ground above low
100.0%
1.0 pts above SD
- Corson
- 100.0%
- SD
- 99.0%
Share of land USGS rates moderate or high potential
Tests reported
2
Too few for a share
- Corson
- 2
- Needed
- 30
2006 to 2015, 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 Corson 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
Corson County, At a glance
Corson County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Corson County in
USGS geologic potential: High across 56% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Corson County, 2006 to 2015, laboratory
CDC holds 2 reported tests for Corson County over the 2006 to 2015 laboratory totals, with a median of 8.0 pCi/L: too few to describe a county (Radon411 reads a share from 30 tests up). Corson County beside the counties around it is how this page reads it.
What these figures count
Only 2 tests were reported to CDC for Corson County over 2006 to 2015 (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: 2006 to 2015, laboratory. Measured data period: 2005 to 2015 (every CDC figure on file).
Corson County, Compared
Corson County radon figures, compared
Calculated by Radon411CDC's largest figure for Corson County rests on 2 tests over the 2006 to 2015 laboratory totals, 1 of them at or above 4 pCi/L, so each test moves its share by 50.0 points and no rank or comparison is drawn from it. Results reached as high as 15.4 pCi/L, with a middle value of 8.0 pCi/L.
Emmons County, ND, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 69.4% of its tests at or above 4 pCi/L. Farther out, Edmunds County (98 miles away) at 61.8%, Meade County (108 miles away) at 54.5% and Hughes County (108 miles away) at 66.7% have figures too. Pooled across 63 South Dakota counties, 58.8% of reported tests reached that level; across every county in the country with a figure, 36.3%.
Statewide for the same period, Bon Homme County reported the highest share (79.5%) and Davison County the lowest (47.9%). EPA's 1993 map puts Corson County in Zone 1, the map's highest label: a predicted county average above 4 pCi/L. USGS geology rates 56% of the county's land high radon potential.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Corson County, Geology
The ground under Corson County
PredictedUSGS's geologic map splits Corson County: 56.2% of its land is high radon potential and 43.8% moderate. The map puts 46.2% of Corson County in the area it calls Missouri Coteau/James River Lowland/Coteau des Prairies and 43.8% in Pierre Hills, with one smaller area beside them. USGS gives the first a radon index of 14, in the high band (12 to 17), and the second 10, in the moderate band (9 to 11).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Missouri Coteau/James River Lowland/Coteau des Prairies | Glacial drift derived largely from Cretaceous marine shale. | High | 14 | 46.2% |
| Pierre Hills | Pierre Shale and Fox Hills sandstone. | Moderate | 10 | 43.8% |
| Great Plains (Unglaciated) | Early Tertiary sandstones. Some units host uranium deposits. | High | 14 | 9.9% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Corson County beside the ground around it
On high-potential ground Corson County is close to South Dakota as a whole: 56.2% of its land against 56.7%. Of the 8 counties that border it, 5 have more high-potential ground, Adams County, ND the most at 100%.
The map rates the ground, not the air in any home.
Local help
Corson County, Local resources
Radon testing and mitigation in Corson County
- South Dakota's radon programDepartment of Agriculture and Natural ResourcesSouth Dakota's radon program offers free or discounted test kits, and answers questions about testing and mitigation in South Dakota.Visit the program’s page(opens in a new tab)
- Free and low-cost kitsThe program says:
The Department of Agriculture and Natural Resources (DANR) will provide 500 free Radon test kits to South Dakota Residents.
- Compare kits
- Professionals in South Dakota5 professionals are listed in South Dakota.
What South Dakota's program says
- Phone
- 1-800-438-3367
What it means
Corson County, Questions
Questions about radon in Corson County
Are radon levels high in Corson County?
Over the 2006 to 2015 laboratory totals, 50.0% of the radon tests reported to CDC for Corson County, South Dakota were at or above 4 pCi/L, and the median reported pre-mitigation result was 8.0 pCi/L. Emmons County, ND, the one bordering county with a figure over the 2006 to 2015 laboratory totals, reported 69.4% of its tests at or above 4 pCi/L.
Which counties border Corson County?
Corson County borders 8 counties: Sioux County, ND, Dewey County, SD, Campbell County, SD, Emmons County, ND, Walworth County, SD, Perkins County, SD, Ziebach County, SD and Adams County, ND.
Products
Corson County, Products
Testing a home in Corson County
No CDC figure names Corson County; the nearest county with one, Edmunds County (98 miles away), reported 61.8% 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 Corson 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
lüft plug-in radon and indoor air quality monitor
- C-NRPP 2024/25: Approved
- Plug-in
- Wi-Fi, Bluetooth
- App only
First reading: Within 90 minutes
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
Corson County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Corson County
Explore
Corson County, Bordering counties
Counties bordering Corson County
Calculated by Radon411- Radon levels in Sioux County, NDEPA zone 1
100.0%at or above 4 pCi/L
Median 9.3 pCi/L · 2 tests
- Radon levels in Ziebach County, SDEPA zone 2
100.0%at or above 4 pCi/L
Median 11.6 pCi/L · 3 tests
- Radon levels in Walworth County, SDEPA zone 1
81.3%at or above 4 pCi/L
Median 6.1 pCi/L · 16 tests
- Radon levels in Adams County, NDEPA zone 1
77.8%at or above 4 pCi/L
Median 8.0 pCi/L · 27 tests
- Radon levels in Emmons County, NDEPA zone 1
69.4%at or above 4 pCi/L
Median 5.9 pCi/L · 49 tests
- Radon levels in Perkins County, SDEPA zone 1
62.5%at or above 4 pCi/L
Median 7.9 pCi/L · 16 tests
- Radon levels in Campbell County, SDEPA zone 1
40.0%at or above 4 pCi/L
Median 3.9 pCi/L · 5 tests
- Radon levels in Dewey County, SDEPA zone 2
0.0%at or above 4 pCi/L
Median 0.6 pCi/L · 1 test
Corson County, Cities and towns
Cities and towns in Corson County
About 3,781 people live in Corson County by the Census Bureau's estimate for July 1, 2025, 110 fewer than in 2020 (−2.8%). Spread over its land, that is 1.5 people to the square mile. No town dominates: McLaughlin, the largest, has 551 residents, 14.6% of the total. Together its 3 incorporated places hold 18.6% of those residents; the other 81.4% live outside any of them. Reported testing is thin here: 2 tests over 2006 to 2015, or 0.5 for every 1,000 residents (2025 estimate), where South Dakota as a whole comes to 5.2.
From McLaughlin to Morristown, CDC publishes no figure by town: each reads Corson County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| McLaughlin | 551 | −2.8% | 14.6% |
| McIntosh | 109 | −4.4% | 2.9% |
| Morristown | 43 | −2.3% | 1.1% |
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).
Corson County, Homes
Homes in Corson County
Corson County is a place of houses on their own lots: 82% of its 1,360 homes are detached single-family houses, against 67% across South Dakota. Half of its homes were built before 1973, close to South Dakota's 1979: 34% date from before 1960 and 18% from 2000 or later. 61% of occupied homes are lived in by their owner (South Dakota: 69%); in the rest a tenant can run a test, but a fix is the landlord's to make.
| Homes | Corson County | South Dakota |
|---|---|---|
| Housing units | 1,360 | 402,364 |
| Detached houses | 82% | 67% |
| In buildings of 5 or more | 1% | 16% |
| Mobile homes | 12% | 8% |
| Built before 1960 | 34% | 29% |
| Built since 2000 | 18% | 28% |
| Middle year built | 1973 | 1979 |
| Owner-occupied | 61% | 69% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.