Illinois Cities Ranked by Indoor Radon Levels

Measured averages from Airthings devices across Illinois, USA. Action level: 4 pCi/L — the threshold at which remediation is recommended.

Milan has the highest measured indoor radon in Illinois at 8.5 pCi/L, based on Airthings measurements across 312 cities.

Updated October 19, 2026

Highest city

8.5pCi/L

Milan

Illinois city average

2.8pCi/L

across 312 cities

Above action level

45/ 312

cities

Illinois Cities Ranked by Indoor Radon Levels
#	Location	Avg level	vs action level
1	Milan	8.5 pCi/L	2.1× over
2	Godfrey	8.2 pCi/L	2.0× over
3	Galesburg	7.5 pCi/L	1.9× over
4	Crystal Lawns	7.4 pCi/L	1.9× over
5	Palos Park	7.2 pCi/L	1.8× over
6	Ingalls Park	6.9 pCi/L	1.7× over
7	Canton	6.7 pCi/L	1.7× over
8	Mattoon	6.4 pCi/L	1.6× over
9	Princeton	6.3 pCi/L	1.6× over
10	Fairbury	6.3 pCi/L	1.6× over
11	Hudson	6.3 pCi/L	1.6× over
12	Beach Park	6.0 pCi/L	1.5× over
13	Mackinaw	5.9 pCi/L	1.5× over
14	East Peoria	5.7 pCi/L	1.4× over
15	Coal Valley	5.7 pCi/L	1.4× over
16	Venetian Village	5.4 pCi/L	1.3× over
17	West Dundee	5.4 pCi/L	1.3× over
18	Jerome	5.3 pCi/L	1.3× over
19	Cherry Valley	5.2 pCi/L	1.3× over
20	Marseilles	5.1 pCi/L	1.3× over
21	Byron	5.0 pCi/L	1.3× over
22	Rochelle	5.0 pCi/L	1.3× over
23	Heyworth	5.0 pCi/L	1.3× over
24	Springfield	4.8 pCi/L	1.2× over
25	Columbia	4.8 pCi/L	1.2× over
26	Sugar Grove	4.7 pCi/L	1.2× over
27	Port Byron	4.7 pCi/L	1.2× over
28	Hampshire	4.7 pCi/L	1.2× over
29	Bellevue	4.6 pCi/L	1.2× over
30	Winnebago	4.6 pCi/L	1.2× over
31	Streator	4.6 pCi/L	1.1× over
32	Sterling	4.5 pCi/L	1.1× over
33	Sheridan	4.4 pCi/L	1.1× over
34	Elgin	4.4 pCi/L	1.1× over
35	Lebanon	4.4 pCi/L	1.1× over
36	Limestone	4.3 pCi/L	1.1× over
37	DeKalb	4.2 pCi/L	1.1× over
38	Wauconda	4.1 pCi/L	1.0× over
39	Carpentersville	4.1 pCi/L	1.0× over
40	Macomb	4.1 pCi/L	1.0× over
41	Bolingbrook	4.1 pCi/L	1.0× over
42	Jacksonville	4.0 pCi/L	1.0× over
43	Lake Villa	4.0 pCi/L	1.0× over
44	Spring Grove	4.0 pCi/L	1.0× over
45	South Elgin	4.0 pCi/L	1.0× over
✓ Below EPA action level (4 pCi/L)
46	East Hazel Crest	4.0 pCi/L	1.0× under
47	Hillside	4.0 pCi/L	1.0× under
48	Monee	4.0 pCi/L	1.0× under
49	Machesney Park	3.9 pCi/L	1.0× under
50	Channahon	3.8 pCi/L	1.0× under
51	Rochester	3.8 pCi/L	0.9× under
52	Elburn	3.7 pCi/L	0.9× under
53	Montgomery	3.7 pCi/L	0.9× under
54	Moline	3.7 pCi/L	0.9× under
55	Urbana	3.7 pCi/L	0.9× under
56	Lake Barrington	3.6 pCi/L	0.9× under
57	Cuba	3.6 pCi/L	0.9× under
58	Paxton	3.6 pCi/L	0.9× under
59	Pekin	3.6 pCi/L	0.9× under
60	Grayslake	3.5 pCi/L	0.9× under
61	Lombard	3.5 pCi/L	0.9× under
62	North Barrington	3.5 pCi/L	0.9× under
63	Metamora	3.5 pCi/L	0.9× under
64	Dixon	3.5 pCi/L	0.9× under
65	Morton	3.5 pCi/L	0.9× under
66	Lindenhurst	3.5 pCi/L	0.9× under
67	Bloomington	3.4 pCi/L	0.9× under
68	Crystal Lake	3.4 pCi/L	0.8× under
69	Galena	3.4 pCi/L	0.8× under
70	Lockport	3.4 pCi/L	0.8× under
71	Morris	3.4 pCi/L	0.8× under
72	Peoria	3.4 pCi/L	0.8× under
73	Sleepy Hollow	3.4 pCi/L	0.8× under
74	Batavia	3.4 pCi/L	0.8× under
75	Indian Head Park	3.4 pCi/L	0.8× under
76	Romeoville	3.3 pCi/L	0.8× under
77	Richmond	3.3 pCi/L	0.8× under
78	Schaumburg	3.3 pCi/L	0.8× under
79	Glen Ellyn	3.3 pCi/L	0.8× under
80	Round Lake	3.3 pCi/L	0.8× under
81	Shorewood	3.2 pCi/L	0.8× under
82	Fairview Heights	3.1 pCi/L	0.8× under
83	Maryville	3.1 pCi/L	0.8× under
84	Freeport	3.1 pCi/L	0.8× under
85	Bourbonnais	3.1 pCi/L	0.8× under
86	Fox Lake Hills	3.1 pCi/L	0.8× under
87	Waukegan	3.1 pCi/L	0.8× under
88	Roselle	3.1 pCi/L	0.8× under
89	West Chicago	3.1 pCi/L	0.8× under
90	Le Roy	3.0 pCi/L	0.8× under
91	Red Bud	3.0 pCi/L	0.8× under
92	Forest Lake	3.0 pCi/L	0.8× under
93	Lincolnshire	3.0 pCi/L	0.8× under
94	Wonder Lake	3.0 pCi/L	0.8× under
95	North Aurora	3.0 pCi/L	0.8× under
96	La Grange Park	3.0 pCi/L	0.8× under
97	Shiloh	3.0 pCi/L	0.8× under
98	South Beloit	3.0 pCi/L	0.8× under
99	Prospect Heights	3.0 pCi/L	0.8× under
100	Roscoe	3.0 pCi/L	0.8× under
101	Carol Stream	3.0 pCi/L	0.7× under
102	New Lenox	3.0 pCi/L	0.7× under
103	O'Fallon	3.0 pCi/L	0.7× under
104	Lake Bluff	3.0 pCi/L	0.7× under
105	Waterloo	3.0 pCi/L	0.7× under
106	Edwardsville	3.0 pCi/L	0.7× under
107	Murphysboro	3.0 pCi/L	0.7× under
108	Troy	2.9 pCi/L	0.7× under
109	Calumet Park	2.9 pCi/L	0.7× under
110	Farmington	2.9 pCi/L	0.7× under
111	Boulder Hill	2.9 pCi/L	0.7× under
112	Bradley	2.9 pCi/L	0.7× under
113	Deer Park	2.9 pCi/L	0.7× under
114	Wheaton	2.9 pCi/L	0.7× under
115	Plano	2.9 pCi/L	0.7× under
116	Quincy	2.9 pCi/L	0.7× under
117	Ottawa	2.9 pCi/L	0.7× under
118	Champaign	2.9 pCi/L	0.7× under
119	Saint Charles	2.9 pCi/L	0.7× under
120	Forsyth	2.8 pCi/L	0.7× under
121	Hampton	2.8 pCi/L	0.7× under
122	Round Lake Beach	2.8 pCi/L	0.7× under
123	Maple Park	2.8 pCi/L	0.7× under
124	Burr Ridge	2.8 pCi/L	0.7× under
125	Northfield	2.8 pCi/L	0.7× under
126	River Forest	2.8 pCi/L	0.7× under
127	Bartlett	2.8 pCi/L	0.7× under
128	Belvidere	2.8 pCi/L	0.7× under
129	Winfield	2.8 pCi/L	0.7× under
130	Yorkville	2.7 pCi/L	0.7× under
131	Addison	2.7 pCi/L	0.7× under
132	Alton	2.7 pCi/L	0.7× under
133	Mundelein	2.7 pCi/L	0.7× under
134	Willowbrook	2.7 pCi/L	0.7× under
135	Lynwood	2.7 pCi/L	0.7× under
136	Minier	2.7 pCi/L	0.7× under
137	Prairie Grove	2.7 pCi/L	0.7× under
138	Barrington Hills	2.7 pCi/L	0.7× under
139	Downers Grove	2.7 pCi/L	0.7× under
140	Dunlap	2.7 pCi/L	0.7× under
141	Manhattan	2.6 pCi/L	0.7× under
142	Peoria Heights	2.6 pCi/L	0.7× under
143	Swansea	2.6 pCi/L	0.7× under
144	Normal	2.6 pCi/L	0.7× under
145	Mokena	2.6 pCi/L	0.7× under
146	Rockford	2.6 pCi/L	0.7× under
147	Geneva	2.6 pCi/L	0.7× under
148	Winthrop Harbor	2.6 pCi/L	0.7× under
149	Homer Glen	2.6 pCi/L	0.6× under
150	Decatur	2.6 pCi/L	0.6× under
151	Green Oaks	2.5 pCi/L	0.6× under
152	Rosemont	2.5 pCi/L	0.6× under
153	Savoy	2.5 pCi/L	0.6× under
154	Crest Hill	2.5 pCi/L	0.6× under
155	Leland Grove	2.5 pCi/L	0.6× under
156	Orland Park	2.5 pCi/L	0.6× under
157	Village of Campton Hills	2.5 pCi/L	0.6× under
158	Algonquin	2.5 pCi/L	0.6× under
159	Peotone	2.5 pCi/L	0.6× under
160	Riverwoods	2.5 pCi/L	0.6× under
161	Long Grove	2.5 pCi/L	0.6× under
162	Woodridge	2.5 pCi/L	0.6× under
163	Lisle	2.5 pCi/L	0.6× under
164	McHenry	2.5 pCi/L	0.6× under
165	Fox River Grove	2.4 pCi/L	0.6× under
166	Mount Zion	2.4 pCi/L	0.6× under
167	Gurnee	2.4 pCi/L	0.6× under
168	Sycamore	2.4 pCi/L	0.6× under
169	Aurora	2.4 pCi/L	0.6× under
170	Itasca	2.4 pCi/L	0.6× under
171	Loves Park	2.4 pCi/L	0.6× under
172	Mount Prospect	2.4 pCi/L	0.6× under
173	Plainfield	2.4 pCi/L	0.6× under
174	Rolling Meadows	2.4 pCi/L	0.6× under
175	Naperville	2.4 pCi/L	0.6× under
176	Glenview	2.4 pCi/L	0.6× under
177	Hanover Park	2.4 pCi/L	0.6× under
178	Gages Lake	2.3 pCi/L	0.6× under
179	Western Springs	2.3 pCi/L	0.6× under
180	Belleville	2.3 pCi/L	0.6× under
181	Fulton	2.3 pCi/L	0.6× under
182	Wadsworth	2.3 pCi/L	0.6× under
183	Elmhurst	2.3 pCi/L	0.6× under
184	Palatine	2.3 pCi/L	0.6× under
185	Palos Heights	2.3 pCi/L	0.6× under
186	Cary	2.3 pCi/L	0.6× under
187	Streamwood	2.3 pCi/L	0.6× under
188	Kildeer	2.3 pCi/L	0.6× under
189	Huntley	2.3 pCi/L	0.6× under
190	Westmont	2.3 pCi/L	0.6× under
191	Pistakee Highlands	2.3 pCi/L	0.6× under
192	Buffalo Grove	2.3 pCi/L	0.6× under
193	Pingree Grove	2.3 pCi/L	0.6× under
194	Wayne	2.3 pCi/L	0.6× under
195	Arlington Heights	2.2 pCi/L	0.6× under
196	Bethalto	2.2 pCi/L	0.6× under
197	Charleston	2.2 pCi/L	0.6× under
198	Lemont	2.2 pCi/L	0.6× under
199	Libertyville	2.2 pCi/L	0.6× under
200	Inverness	2.2 pCi/L	0.5× under
201	Darien	2.2 pCi/L	0.5× under
202	Davis Junction	2.2 pCi/L	0.5× under
203	Warrenville	2.2 pCi/L	0.5× under
204	Washington	2.2 pCi/L	0.5× under
205	Fairfield	2.1 pCi/L	0.5× under
206	Vernon Hills	2.1 pCi/L	0.5× under
207	Grandwood Park	2.1 pCi/L	0.5× under
208	Marion	2.1 pCi/L	0.5× under
209	East Moline	2.1 pCi/L	0.5× under
210	West Peoria	2.1 pCi/L	0.5× under
211	Goodings Grove	2.1 pCi/L	0.5× under
212	Oswego	2.1 pCi/L	0.5× under
213	Rockton	2.1 pCi/L	0.5× under
214	Woodstock	2.1 pCi/L	0.5× under
215	Hawthorn Woods	2.1 pCi/L	0.5× under
216	Lake in the Hills	2.1 pCi/L	0.5× under
217	Round Lake Heights	2.1 pCi/L	0.5× under
218	Evergreen Park	2.1 pCi/L	0.5× under
219	Gilberts	2.1 pCi/L	0.5× under
220	Villa Park	2.1 pCi/L	0.5× under
221	Wood Dale	2.1 pCi/L	0.5× under
222	Lakewood	2.1 pCi/L	0.5× under
223	Antioch	2.1 pCi/L	0.5× under
224	Poplar Grove	2.1 pCi/L	0.5× under
225	Round Lake Park	2.0 pCi/L	0.5× under
226	South Barrington	2.0 pCi/L	0.5× under
227	Collinsville	2.0 pCi/L	0.5× under
228	Morton Grove	2.0 pCi/L	0.5× under
229	Berwyn	2.0 pCi/L	0.5× under
230	Clarendon Hills	2.0 pCi/L	0.5× under
231	Glendale Heights	2.0 pCi/L	0.5× under
232	Bloomingdale	2.0 pCi/L	0.5× under
233	Winnetka	2.0 pCi/L	0.5× under
234	Marengo	2.0 pCi/L	0.5× under
235	Braidwood	2.0 pCi/L	0.5× under
236	Des Plaines	2.0 pCi/L	0.5× under
237	Fox Lake	2.0 pCi/L	0.5× under
238	Northbrook	1.9 pCi/L	0.5× under
239	Palos Hills	1.9 pCi/L	0.5× under
240	Frankfort Square	1.9 pCi/L	0.5× under
241	Barrington	1.9 pCi/L	0.5× under
242	Highland Park	1.9 pCi/L	0.5× under
243	Knollwood	1.9 pCi/L	0.5× under
244	Zion	1.9 pCi/L	0.5× under
245	La Grange	1.9 pCi/L	0.5× under
246	Germantown Hills	1.9 pCi/L	0.5× under
247	Park Ridge	1.9 pCi/L	0.5× under
248	Lake of the Woods	1.9 pCi/L	0.5× under
249	Wheeling	1.9 pCi/L	0.5× under
250	Countryside	1.9 pCi/L	0.5× under
251	Flossmoor	1.9 pCi/L	0.5× under
252	Mahomet	1.9 pCi/L	0.5× under
253	Brookfield	1.8 pCi/L	0.5× under
254	Oakbrook Terrace	1.8 pCi/L	0.5× under
255	Oak Park	1.8 pCi/L	0.5× under
256	Frankfort	1.8 pCi/L	0.5× under
257	Hinckley	1.8 pCi/L	0.5× under
258	Orland Hills	1.8 pCi/L	0.5× under
259	Forest Park	1.8 pCi/L	0.4× under
260	Lake Zurich	1.8 pCi/L	0.4× under
261	Long Lake	1.8 pCi/L	0.4× under
262	Oakwood Hills	1.8 pCi/L	0.4× under
263	Lake Forest	1.8 pCi/L	0.4× under
264	Cicero	1.8 pCi/L	0.4× under
265	Merrionette Park	1.8 pCi/L	0.4× under
266	Hoffman Estates	1.8 pCi/L	0.4× under
267	Willow Springs	1.8 pCi/L	0.4× under
268	Twin Grove	1.7 pCi/L	0.4× under
269	Oak Brook	1.7 pCi/L	0.4× under
270	Oak Forest	1.7 pCi/L	0.4× under
271	Wasco	1.7 pCi/L	0.4× under
272	Bull Valley	1.7 pCi/L	0.4× under
273	Sherman	1.7 pCi/L	0.4× under
274	Paris	1.7 pCi/L	0.4× under
275	Carbondale	1.7 pCi/L	0.4× under
276	Hinsdale	1.6 pCi/L	0.4× under
277	Minooka	1.6 pCi/L	0.4× under
278	North Peoria	1.6 pCi/L	0.4× under
279	Bannockburn	1.6 pCi/L	0.4× under
280	Hometown	1.6 pCi/L	0.4× under
281	Highwood	1.6 pCi/L	0.4× under
282	Elk Grove Village	1.6 pCi/L	0.4× under
283	Niles	1.6 pCi/L	0.4× under
284	Deerfield	1.6 pCi/L	0.4× under
285	Joliet	1.6 pCi/L	0.4× under
286	Hickory Hills	1.5 pCi/L	0.4× under
287	Chillicothe	1.5 pCi/L	0.4× under
288	Glencoe	1.5 pCi/L	0.4× under
289	Hanna City	1.4 pCi/L	0.4× under
290	Saint Joseph	1.4 pCi/L	0.4× under
291	Bensenville	1.4 pCi/L	0.4× under
292	Harwood Heights	1.4 pCi/L	0.3× under
293	Sandwich	1.4 pCi/L	0.3× under
294	Glen Carbon	1.3 pCi/L	0.3× under
295	Chatham	1.3 pCi/L	0.3× under
296	Lincolnwood	1.3 pCi/L	0.3× under
297	Wilmette	1.3 pCi/L	0.3× under
298	Riverside	1.3 pCi/L	0.3× under
299	Tinley Park	1.3 pCi/L	0.3× under
300	Norridge	1.2 pCi/L	0.3× under
301	Elmwood Park	1.2 pCi/L	0.3× under
302	Westchester	1.2 pCi/L	0.3× under
303	Tower Lake	1.1 pCi/L	0.3× under
304	Oak Lawn	1.1 pCi/L	0.3× under
305	Stickney	1.1 pCi/L	0.3× under
306	Burbank	1.1 pCi/L	0.3× under
307	Homewood	1.1 pCi/L	0.3× under
308	Skokie	1.0 pCi/L	0.3× under
309	Chicago	0.8 pCi/L	0.2× under
310	Grandview	0.7 pCi/L	0.2× under
311	Kenilworth	0.7 pCi/L	0.2× under
312	Evanston	0.6 pCi/L	0.2× under

See USA cities ranked by radon level See all States ranked by radon level