Radon in Kentucky: radon map by county

EPA's Map of Radon Zones puts 30 of Kentucky's 120 counties in Zone 1 (predicted average indoor radon above 4 pCi/L), 82 in Zone 2 and 8 in Zone 3. Of 20,870 building tests that radon laboratories reported for 2008 to 2017, 42.8% were at or above EPA's 4 pCi/L action level, against 36.5% nationally (number 11 of 42 states with 1,000+ tests). The highest county share is Meade County (68.4% of 78 tests).

counties in Zone 1 (above 4 pCi/L predicted)

counties in Zone 2 (2 to 4)

counties in Zone 3 (below 2)

42.8%

of 20,870 lab tests at or above 4 pCi/L

Radon by county in Kentucky

EPA radon zone and radon test results for each county in Kentucky
County	EPA zone	Lab tests	Median	4+ pCi/L
Adair County	Zone 1	42	3.8	43.4%
Allen County	Zone 1	44	1.9	29.3%
Anderson County	Zone 2	152	2.2	25.2%
Ballard County	Zone 3	4	1.4	0%
Barren County	Zone 1	138	4.0	51.6%
Bath County	Zone 2	12	3.1	41.7%
Bell County	Zone 2	7	1.3	12.5%
Boone County	Zone 2	1,112	3.5	42.9%
Bourbon County	Zone 1	88	4.8	53.5%
Boyd County	Zone 2	158	2.1	17.9%
Boyle County	Zone 1	302	4.4	53.9%
Bracken County	Zone 2	5	2.0	20%
Breathitt County	Zone 2	43	1.7	19.1%
Breckinridge County	Zone 2	24	2.5	31.3%
Bullitt County	Zone 1	443	3.6	47.5%
Butler County	Zone 2	23	1.5	3.8%
Caldwell County	Zone 2	15	3.7	40%
Calloway County	Zone 3	23	2.4	22.2%
Campbell County	Zone 2	455	2.3	26.2%
Carlisle County	Zone 3	1	2.0	0%
Carroll County	Zone 2	22	3.5	38.5%
Carter County	Zone 2	37	2.2	31.7%
Casey County	Zone 1	31	3.1	32.6%
Christian County	Zone 2	58	3.2	36.1%
Clark County	Zone 1	180	2.4	29%
Clay County	Zone 2	7	2.1	20%
Clinton County	Zone 2	31	3.5	47.5%
Crittenden County	Zone 2	7	1.6	25%
Cumberland County	Zone 1	12	4.6	55.6%
Daviess County	Zone 2	90	1.8	20%
Edmonson County	Zone 2	49	1.6	21%
Elliott County	Zone 2	5	3.5	40%
Estill County	Zone 2	126	3.2	44.1%
Fayette County	Zone 1	3,323	4.5	54.5%
Fleming County	Zone 2	17	2.9	36.4%
Floyd County	Zone 2	13	2.7	40%
Franklin County	Zone 1	453	3.3	43.1%
Fulton County	Zone 3	1	1.9	0%
Gallatin County	Zone 2	13	2.5	25%
Garrard County	Zone 2	119	2.6	39.6%
Grant County	Zone 2	68	2.5	33.3%
Graves County	Zone 3	21	1.5	8.3%
Grayson County	Zone 2	32	2.2	27.8%
Green County	Zone 1	24	2.5	32.3%
Greenup County	Zone 2	91	2.0	12.5%
Hancock County	Zone 2	5	1.4	16.7%
Hardin County	Zone 2	341	4.0	50.3%
Harlan County	Zone 2	4	0.1	25%
Harrison County	Zone 1	81	3.4	46.8%
Hart County	Zone 1	66	8.0	65.5%
Henderson County	Zone 2	46	2.3	24.1%
Henry County	Zone 2	33	3.2	36.6%
Hickman County	Zone 3	4	0.1	0%
Hopkins County	Zone 2	33	1.7	9.5%
Jackson County	Zone 2	9	1.8	0%
Jefferson County	Zone 1	5,028	2.7	39.4%
Jessamine County	Zone 1	517	4.7	55.5%
Johnson County	Zone 2	27	0.8	0%
Kenton County	Zone 2	952	2.3	26%
Knott County	Zone 2	11	1.7	23.1%
Knox County	Zone 2	23	2.1	10.3%
Larue County	Zone 2	29	3.7	47.1%
Laurel County	Zone 2	84	1.9	22%
Lawrence County	Zone 2	8	1.7	0%
Lee County	Zone 2	13	1.2	5.6%
Leslie County	Zone 2	5	0.1	10%
Letcher County	Zone 2	19	1.8	31.8%
Lewis County	Zone 2	8	2.8	33.3%
Lincoln County	Zone 1	93	2.8	35.6%
Livingston County	Zone 2	6	1.3	0%
Logan County	Zone 2	64	2.4	31.6%
Lyon County	Zone 2	13	2.5	35.7%
Madison County	Zone 2	438	2.9	38.7%
Magoffin County	Zone 2	8	0.5	0%
Marion County	Zone 1	113	3.9	48.6%
Marshall County	Zone 3	78	1.5	10.6%
Martin County	Zone 2	2	0.1	0%
Mason County	Zone 2	25	2.6	25%
McCracken County	Zone 3	22	1.6	21.4%
McCreary County	Zone 2	8	1.2	0%
McLean County	Zone 2	2	6.7	50%
Meade County	Zone 2	78	8.2	68.4%
Menifee County	Zone 2	37	1.4	22%
Mercer County	Zone 1	197	2.7	38.2%
Metcalfe County	Zone 1	25	3.5	45.5%
Monroe County	Zone 1	61	4.6	52.9%
Montgomery County	Zone 2	84	4.1	51.4%
Morgan County	Zone 2	15	1.2	5.6%
Muhlenberg County	Zone 2	16	2.3	17.6%
Nelson County	Zone 1	218	6.3	66.1%
Nicholas County	Zone 2	17	1.9	10%
Ohio County	Zone 2	16	1.9	11.8%
Oldham County	Zone 2	595	2.7	37.1%
Owen County	Zone 2	43	2.5	36.2%
Owsley County	Zone 2	5	18.3	62.5%
Pendleton County	Zone 1	26	1.9	26.5%
Perry County	Zone 2	22	1.4	20.8%
Pike County	Zone 2	73	1.1	17.1%
Powell County	Zone 2	23	3.2	44.8%
Pulaski County	Zone 1	277	5.1	59.5%
Robertson County	Zone 1	4	1.1	25%
Rockcastle County	Zone 2	11	3.0	42.9%
Rowan County	Zone 2	69	1.6	18.9%
Russell County	Zone 1	25	2.9	25%
Scott County	Zone 1	656	3.6	46.9%
Shelby County	Zone 2	289	3.0	37.6%
Simpson County	Zone 2	106	2.6	32.5%
Spencer County	Zone 2	136	2.5	31.3%
Taylor County	Zone 1	70	4.4	57.1%
Todd County	Zone 2	55	1.8	17.7%
Trigg County	Zone 2	28	2.4	22.2%
Trimble County	Zone 2	18	3.7	45.8%
Union County	Zone 2	8	1.6	25%
Warren County	Zone 1	1,046	6.3	61.5%
Washington County	Zone 2	40	2.4	27.3%
Wayne County	Zone 2	53	5.0	60.9%
Webster County	Zone 2	7	2.0	12.5%
Whitley County	Zone 2	21	1.6	4.3%
Wolfe County	Zone 2	4	0.1	0%
Woodford County	Zone 1	257	4.9	57.9%

Lab tests: buildings tested by radon laboratories, 2008 to 2017; median in pCi/L; “4+ pCi/L” is the share of tests at or above EPA's action level. n/a: no value on file (no tests, or too few to report).

What the zones mean

Zone 1 counties have a predicted average indoor radon screening level above 4 pCi/L, Zone 2 from 2 to 4 pCi/L and Zone 3 below 2 pCi/L. The prediction is from 1993 indoor measurements, geology, aerial radioactivity, soils and foundation types. EPA: “This map should not be used to determine if individual homes need to be tested.” EPA recommends fixing a home at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of exposure.

Radon in Kentucky: questions

What radon zone is Kentucky?

EPA's 1993 map does not give states one zone; it zones each county. In Kentucky, 30 counties are Zone 1, 82 Zone 2 and 8 Zone 3. EPA says the map "should not be used to determine if individual homes need to be tested".

Which Kentucky counties have the highest radon levels?

By the share of laboratory tests at or above 4 pCi/L for 2008 to 2017 (counties with 20 or more tests): Meade County 68.4% (median 8.2 pCi/L, 78 tests); Nelson County 66.1% (median 6.3 pCi/L, 218 tests); Hart County 65.5% (median 8.0 pCi/L, 66 tests); Warren County 61.5% (median 6.3 pCi/L, 1,046 tests); Wayne County 60.9% (median 5.0 pCi/L, 53 tests).

How common is high radon in Kentucky?

42.8% of the 20,870 tests in the laboratory data for Kentucky (2008 to 2017) were at or above 4 pCi/L; the national share was 36.5%. Buildings are tested by choice, often because of a sale or a concern, so the share describes the tests on file, not every home.

Should I test for radon in Kentucky?

Yes. EPA recommends testing every home no matter where it is, fixing it at 4 pCi/L or more and considering a fix between 2 and 4 pCi/L, because there is no known safe level of radon exposure.

States bordering Kentucky

Radon in Illinois (56 of 102 in Zone 1)Radon in Indiana (57 of 92 in Zone 1)Radon in Missouri (11 of 115 in Zone 1)Radon in Ohio (53 of 88 in Zone 1)Radon in Tennessee (39 of 95 in Zone 1)Radon in Virginia (62 of 133 in Zone 1)Radon in West Virginia (20 of 55 in Zone 1)

Other free hazard lookups

All of these, plus wetlands, FEMA hazard ratings and the federal contamination lists, are in the Environmental Records Report for any US address ($29).

Superfund sites in Kentucky · Radon map of every state

Data compiled 2026-10-20. County-level screening information, not a radon measurement of any building.