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 Hancock County, Illinois
EPA puts Hancock County in Zone 1, its highest radon zone, and 33.3% of its 63 reported radon tests (2017) 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
Share at 4+ pCi/L
33.3%
0.4 pts below IL
- Hancock
- 33.3%
- Illinois
- 33.7%
63 tests, 2017
Median result
2.8pCi/L
Below action level
- Hancock
- 2.8 pCi/L
- EPA
- 4.0 pCi/L
Midpoint of the tests, 2017
Tests reported
63
57th of 70 by tests
- Hancock
- 63
- Cook
- 26,937
Reported to CDC before any fix, 2017
EPA radon zone
Zone 1
Highest potential
- Zone 1
- 2
- 3
1 highest, 3 lowest
EPA predicts over 4 pCi/L indoors
Rank in Illinois
54 of 70
Lowest quarter
- Hancock
- 33.3%
- Stark
- 69.2%
By share, of 70 with 30+ tests
Read a result for Hancock County
Starts at Hancock County's median, 2.8 pCi/L
EPA’s own thresholds; the figures are the area’s, never this home’s.
EPA’s reading of 2.8 pCi/L
Between 2 and 4 pCi/L
- Under 20 to 1.9 pCi/L
- 2 to 4consider a fix
- 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. Hancock County's median reported result, 2017.
The data
Hancock County, At a glance
Hancock County at a glance
Predicted: EPA radon zone
EPA Zone 1: highest predicted potential
EPA puts all of Hancock County in
USGS geologic potential: High across 100% of the county's area
Predicted: EPA Map of Radon Zones
Measured: tests reported to CDC
Radon tests reported for Hancock County, 2017
| Year | Share of reported tests at or above 4 pCi/L |
|---|---|
| 2014 | 36.8% |
| 2015 | 50.0% |
| 2017 | 33.3% |
2017: 33.3%. Across these years the share ran from 33.3% to 50.0%. Each column counts radon tests reported to CDC that year, not homes.
What these figures count
These are the 63 tests reported to CDC for Hancock County over 2017, 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: 2017. Measured data period: 2005 to 2017 (every CDC figure on file).
Hancock County, Compared
Hancock County radon figures, compared
Calculated by Radon411In Hancock County, about 3 in 10 reported tests in 2017 (21 of 63) were at or above EPA's action level. Against the national pool of 31.7%, the gap is 1.6 points higher. Across 93 Illinois counties pooled together, 33.7% of tests reached that level, so Hancock County runs 0.4 points below its state.
Of 2 neighbours with a figure, all 2 reported a larger share at or above 4 pCi/L; the spread is 46.1% (Adams County) to 55.7% (McDonough County). By share, Hancock County is 54th of 70 Illinois counties with 30 or more tests for the same period.
Half the tests came in under 2.8 pCi/L and half over it; the single highest reached 12.2 pCi/L. Below the action level, 15 tests (23.8%) came in under 2 pCi/L, against 37.7% statewide, and 27 tests (42.9%) fell between 2 and 4, against 28.6% statewide.
Zone 1 on EPA's map (predicted average above 4 pCi/L) and a 33.3% share point the same way here. USGS geology rates 100% of the county's land high radon potential.
The busiest year on file was 2014, with 114 tests reported; the quietest, 2015, had 6.
Pooled shares: Radon411's sum of CDC's county counts for one period.
Hancock County, Geology
The ground under Hancock County
PredictedUSGS's geologic map puts all of Hancock County's mapped land in one class: high radon potential. All of it lies in the area the map calls Galesburg Plain, to which USGS gives a radon index of 13, in the high band (12 to 17).
| Area | The rock, in USGS's words | Potential | Radon index | Share of land |
|---|---|---|---|---|
| Galesburg Plain | Illinoian glacial deposits and loess over Paleozoic sedimentary rocks. | High | 13 | 99.7% |
Names, descriptions and indexes: U.S. Geological Survey, Geologic Radon Potential Map (2025). Shares: Radon411, from the map cut to the boundary.
Hancock County beside the ground around it
Hancock County has more high-potential ground than Illinois as a whole: 100% of its land against 64.5%. Of the 7 counties that border it, none has as large a share of high-potential ground; McDonough County comes nearest at 100%.
The map rates the ground, not the air in any home.
Local help
Hancock County, Local resources
Radon testing and mitigation in Hancock County
Listed radon businesses with an address in Hancock County:
- IEMA-OHS Radon ProgramIEMA-OHS Radon Program, run by Illinois Emergency Management Agency and Office of Homeland Security, licenses or certifies radon professionals and states the rule for disclosing radon when a home is sold, and answers questions about testing and mitigation in Illinois.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 Illinois339 professionals are listed in Illinois.
Listed radon professionals by town: Nauvoo
What Illinois's program says
- Phone
- (800) 325-1245
- Licensing of radon professionals
The Agency also licenses and regulates the individuals who provide radon measurement and mitigation to the public.
- Disclosure when a home is sold or rented
Illinois Radon Awareness Act - This is the legislation that requires the seller to provide to the buyer of any interest in residential real property the IEMA-OHS pamphlet entitled "Radon Testing Guidelines for Real Estate Transactions" and the Illinois Disclosure of Information on Radon Hazards.
What it means
Hancock County, Questions
Questions about radon in Hancock County
Are radon levels high in Hancock County?
In 2017, 33.3% of the radon tests reported to CDC for Hancock County, Illinois were at or above 4 pCi/L, and the median reported pre-mitigation result was 2.8 pCi/L. Of 70 Illinois counties with 30 or more tests for the same period, 53 reported a higher share; pooled, the state comes to 33.7%.
Which counties border Hancock County?
Hancock County borders 7 counties: Lee County, IA, McDonough County, IL, Adams County, IL, Clark County, MO, Schuyler County, IL, Henderson County, IL and Lewis County, MO.
Products
Hancock County, Products
Testing a home in Hancock County
In Hancock County, 33.3% of 63 tests reported to CDC in 2017 reached 4 pCi/L, against 33.7% pooled across Illinois. In Zone 1 the year-round level in Hancock 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-1085 palm-sized rechargeable radon detector
- C-NRPP 2024/25: Not included
- Battery
- Alarm
- Screen
Method: Semiconductor sensor
First reading: Within 6 hours
Short-term kit
Radon Short Term Test Kit short-term charcoal radon test kit, lab fee included
- Lab fee included
Method: Charcoal
In home: 2 to 7 days
- See every kit and monitor Test kits and monitors
Test kits and monitors: 1 of 3
Hancock County is in EPA Zone 1, the highest predicted radon potential. Best radon monitors for Zone 1 counties like Hancock County
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Hancock County, Bordering counties
Counties bordering Hancock County
Calculated by Radon411- Radon levels in McDonough County, ILEPA zone 1
55.7%at or above 4 pCi/L
Median 4.3 pCi/L · 210 tests · 22.4 points above Hancock County
- Radon levels in Adams County, ILEPA zone 1
46.1%at or above 4 pCi/L
Median 3.6 pCi/L · 885 tests · 12.8 points above Hancock County
- Radon levels in Lewis County, MOEPA zone 2
25.0%at or above 4 pCi/L
Median 1.4 pCi/L · 4 tests · 8.3 points below Hancock County
- Radon levels in Lee County, IAEPA zone 1
No CDC figure for 2017; its page reads it against its own neighbours.
- Radon levels in Clark County, MOEPA zone 2
No CDC figure for 2017; its page reads it against its own neighbours.
- Radon levels in Schuyler County, ILEPA zone 1
No CDC figure for 2017; its page reads it against its own neighbours.
- Radon levels in Henderson County, ILEPA zone 1
No CDC figure for 2017; its page reads it against its own neighbours.
Hancock County, Cities and towns
Cities and towns in Hancock County
About 16,803 people live in Hancock County by the Census Bureau's estimate for July 1, 2025, 767 fewer than in 2020 (−4.4%). That works out to 21 people per square mile of land. No town dominates: Hamilton, the largest, has 2,624 residents, 15.6% of the total. Reported testing is thin here: 63 tests over 2017, or 3.7 for every 1,000 residents (2025 estimate), where Illinois as a whole comes to 10.9.
From Hamilton to Bentley, CDC publishes no figure by town: each reads Hancock County's.
| Place | Residents | Since 2020 | Share of residents |
|---|---|---|---|
| Hamilton | 2,624 | −4.4% | 15.6% |
| Carthage | 2,393 | −4.1% | 14.2% |
| Warsaw | 1,436 | −4.6% | 8.5% |
| La Harpe | 1,124 | −4.0% | 6.7% |
| Nauvoo | 895 | −4.7% | 5.3% |
| Dallas Cityextends beyond Hancock County | 767 | −5.0% | Counted whole |
| Augusta | 531 | −4.3% | 3.2% |
| Bowen | 441 | −4.3% | 2.6% |
| Plymouthextends beyond Hancock County | 416 | −4.4% | Counted whole |
| Elvaston | 141 | −4.7% | 0.8% |
| West Point | 136 | −4.9% | 0.8% |
| Ferris | 124 | −4.6% | 0.7% |
- Pontoosuc
- Basco
- Bentley
15 incorporated places, as listed in the U.S. Census Bureau’s 2020 place reference files. “(part)” marks a place that extends into another county. Residents: U.S. Census Bureau population estimates for July 1, 2025 (Vintage 2025). A place that extends beyond Hancock County is counted whole, so it has no share.
Hancock County, Homes
Homes in Hancock County
Hancock County is a place of houses on their own lots: 82% of its 8,959 homes are detached single-family houses, against 58% across Illinois. Half of its homes were built before 1963, close to Illinois' 1970: 47% date from before 1960 and 10% from 2000 or later. Owners live in 81% of the occupied homes (Illinois: 67%), so for most households a test and a fix are their own to order.
| Homes | Hancock County | Illinois |
|---|---|---|
| Housing units | 8,959 | 5,443,501 |
| Detached houses | 82% | 58% |
| In buildings of 5 or more | 4% | 22% |
| Mobile homes | 6% | 2% |
| Built before 1960 | 47% | 38% |
| Built since 2000 | 10% | 16% |
| Middle year built | 1963 | 1970 |
| Owner-occupied | 81% | 67% |
Census Bureau, American Community Survey, 2019 to 2023: estimates from a sample of homes, looser for a small place. Shares by Radon411.