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 8.9 pCi/L, based on Airthings measurements across 310 cities.

Updated September 28, 2026

Highest city

8.9pCi/L

Milan

Illinois city average

2.8pCi/L

across 310 cities

Above action level

43/ 310

cities

Illinois Cities Ranked by Indoor Radon Levels
#	Location	Avg level	vs action level
1	Milan	8.9 pCi/L	2.2× 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	Fairbury	6.6 pCi/L	1.6× over
9	Mattoon	6.4 pCi/L	1.6× over
10	Princeton	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	Coal Valley	5.7 pCi/L	1.4× over
15	Venetian Village	5.4 pCi/L	1.3× over
16	West Dundee	5.3 pCi/L	1.3× over
17	Jerome	5.3 pCi/L	1.3× over
18	Marseilles	5.1 pCi/L	1.3× over
19	Byron	5.0 pCi/L	1.3× over
20	Rochelle	5.0 pCi/L	1.3× over
21	Hampshire	5.0 pCi/L	1.3× over
22	Heyworth	5.0 pCi/L	1.3× over
23	Sugar Grove	4.9 pCi/L	1.2× over
24	Cherry Valley	4.8 pCi/L	1.2× over
25	Springfield	4.8 pCi/L	1.2× over
26	Bellevue	4.8 pCi/L	1.2× over
27	Columbia	4.8 pCi/L	1.2× over
28	Port Byron	4.7 pCi/L	1.2× over
29	Winnebago	4.6 pCi/L	1.2× over
30	Streator	4.6 pCi/L	1.1× over
31	Sterling	4.5 pCi/L	1.1× over
32	Elgin	4.5 pCi/L	1.1× over
33	Sheridan	4.4 pCi/L	1.1× over
34	Lebanon	4.4 pCi/L	1.1× over
35	Limestone	4.3 pCi/L	1.1× over
36	DeKalb	4.3 pCi/L	1.1× over
37	Wauconda	4.2 pCi/L	1.1× over
38	Bolingbrook	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	Lake Villa	4.0 pCi/L	1.0× over
42	Spring Grove	4.0 pCi/L	1.0× over
43	South Elgin	4.0 pCi/L	1.0× over
✓ Below EPA action level (4 pCi/L)
44	East Hazel Crest	4.0 pCi/L	1.0× under
45	Hillside	4.0 pCi/L	1.0× under
46	Jacksonville	4.0 pCi/L	1.0× under
47	Monee	4.0 pCi/L	1.0× under
48	Machesney Park	3.9 pCi/L	1.0× under
49	Lindenhurst	3.8 pCi/L	0.9× under
50	Rochester	3.8 pCi/L	0.9× under
51	Elburn	3.7 pCi/L	0.9× under
52	Montgomery	3.7 pCi/L	0.9× under
53	Moline	3.7 pCi/L	0.9× under
54	North Barrington	3.7 pCi/L	0.9× under
55	Peoria	3.7 pCi/L	0.9× under
56	Cuba	3.6 pCi/L	0.9× under
57	Paxton	3.6 pCi/L	0.9× under
58	Pekin	3.6 pCi/L	0.9× under
59	Urbana	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	Dixon	3.5 pCi/L	0.9× under
63	Sleepy Hollow	3.5 pCi/L	0.9× under
64	Metamora	3.5 pCi/L	0.9× under
65	Bloomington	3.4 pCi/L	0.9× under
66	Crystal Lake	3.4 pCi/L	0.9× under
67	Channahon	3.4 pCi/L	0.9× under
68	Lake Barrington	3.4 pCi/L	0.9× under
69	Bourbonnais	3.4 pCi/L	0.8× under
70	Galena	3.4 pCi/L	0.8× under
71	Lockport	3.4 pCi/L	0.8× under
72	Morris	3.4 pCi/L	0.8× under
73	Morton	3.4 pCi/L	0.8× under
74	Indian Head Park	3.4 pCi/L	0.8× under
75	Glen Ellyn	3.3 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	Fairview Heights	3.3 pCi/L	0.8× under
80	Batavia	3.3 pCi/L	0.8× under
81	Round Lake	3.3 pCi/L	0.8× under
82	Maryville	3.1 pCi/L	0.8× under
83	Shorewood	3.1 pCi/L	0.8× under
84	Freeport	3.1 pCi/L	0.8× under
85	O'Fallon	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	Le Roy	3.0 pCi/L	0.8× under
90	Forest Lake	3.0 pCi/L	0.8× under
91	Forsyth	3.0 pCi/L	0.8× under
92	Lincolnshire	3.0 pCi/L	0.8× under
93	Wonder Lake	3.0 pCi/L	0.8× under
94	North Aurora	3.0 pCi/L	0.8× under
95	Swansea	3.0 pCi/L	0.8× under
96	La Grange Park	3.0 pCi/L	0.8× under
97	South Beloit	3.0 pCi/L	0.8× under
98	Roscoe	3.0 pCi/L	0.8× under
99	West Chicago	3.0 pCi/L	0.8× under
100	Carol Stream	3.0 pCi/L	0.7× under
101	Prospect Heights	3.0 pCi/L	0.7× under
102	Hampton	3.0 pCi/L	0.7× under
103	New Lenox	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	Burr Ridge	3.0 pCi/L	0.7× under
107	Edwardsville	3.0 pCi/L	0.7× under
108	Murphysboro	3.0 pCi/L	0.7× under
109	Saint Charles	3.0 pCi/L	0.7× under
110	Troy	2.9 pCi/L	0.7× under
111	Calumet Park	2.9 pCi/L	0.7× under
112	Wheaton	2.9 pCi/L	0.7× under
113	Farmington	2.9 pCi/L	0.7× under
114	Boulder Hill	2.9 pCi/L	0.7× under
115	Bradley	2.9 pCi/L	0.7× under
116	Deer Park	2.9 pCi/L	0.7× under
117	Plano	2.9 pCi/L	0.7× under
118	Quincy	2.9 pCi/L	0.7× under
119	Decatur	2.9 pCi/L	0.7× under
120	Ottawa	2.9 pCi/L	0.7× under
121	Shiloh	2.9 pCi/L	0.7× under
122	Round Lake Beach	2.8 pCi/L	0.7× under
123	Winfield	2.8 pCi/L	0.7× under
124	Bartlett	2.8 pCi/L	0.7× under
125	Belvidere	2.8 pCi/L	0.7× under
126	River Forest	2.8 pCi/L	0.7× under
127	Northfield	2.8 pCi/L	0.7× under
128	Lynwood	2.7 pCi/L	0.7× under
129	Yorkville	2.7 pCi/L	0.7× under
130	Addison	2.7 pCi/L	0.7× under
131	Alton	2.7 pCi/L	0.7× under
132	Mundelein	2.7 pCi/L	0.7× under
133	Minier	2.7 pCi/L	0.7× under
134	Prairie Grove	2.7 pCi/L	0.7× under
135	Barrington Hills	2.7 pCi/L	0.7× under
136	Crest Hill	2.7 pCi/L	0.7× under
137	Dunlap	2.7 pCi/L	0.7× under
138	Normal	2.6 pCi/L	0.7× under
139	Manhattan	2.6 pCi/L	0.7× under
140	Peoria Heights	2.6 pCi/L	0.7× under
141	Champaign	2.6 pCi/L	0.7× under
142	Loves Park	2.6 pCi/L	0.7× under
143	Downers Grove	2.6 pCi/L	0.7× under
144	Geneva	2.6 pCi/L	0.7× under
145	Winthrop Harbor	2.6 pCi/L	0.7× under
146	Homer Glen	2.6 pCi/L	0.6× under
147	Rockford	2.6 pCi/L	0.6× under
148	Savoy	2.6 pCi/L	0.6× under
149	Mokena	2.6 pCi/L	0.6× under
150	Green Oaks	2.5 pCi/L	0.6× under
151	Rosemont	2.5 pCi/L	0.6× under
152	Willowbrook	2.5 pCi/L	0.6× under
153	Leland Grove	2.5 pCi/L	0.6× under
154	Village of Campton Hills	2.5 pCi/L	0.6× under
155	Algonquin	2.5 pCi/L	0.6× under
156	Peotone	2.5 pCi/L	0.6× under
157	Riverwoods	2.5 pCi/L	0.6× under
158	Sycamore	2.5 pCi/L	0.6× under
159	Woodridge	2.5 pCi/L	0.6× under
160	Fox River Grove	2.5 pCi/L	0.6× under
161	Lisle	2.5 pCi/L	0.6× under
162	McHenry	2.5 pCi/L	0.6× under
163	Rolling Meadows	2.5 pCi/L	0.6× under
164	Mount Zion	2.4 pCi/L	0.6× under
165	Aurora	2.4 pCi/L	0.6× under
166	Itasca	2.4 pCi/L	0.6× under
167	Gurnee	2.4 pCi/L	0.6× under
168	Long Grove	2.4 pCi/L	0.6× under
169	Mount Prospect	2.4 pCi/L	0.6× under
170	Plainfield	2.4 pCi/L	0.6× under
171	Gages Lake	2.4 pCi/L	0.6× under
172	Hanover Park	2.4 pCi/L	0.6× under
173	Naperville	2.4 pCi/L	0.6× under
174	Elmhurst	2.4 pCi/L	0.6× under
175	Glenview	2.4 pCi/L	0.6× under
176	Streamwood	2.3 pCi/L	0.6× under
177	Western Springs	2.3 pCi/L	0.6× under
178	Fulton	2.3 pCi/L	0.6× under
179	Orland Park	2.3 pCi/L	0.6× under
180	Wadsworth	2.3 pCi/L	0.6× under
181	Palos Heights	2.3 pCi/L	0.6× under
182	Cary	2.3 pCi/L	0.6× under
183	Kildeer	2.3 pCi/L	0.6× under
184	Huntley	2.3 pCi/L	0.6× under
185	Oswego	2.3 pCi/L	0.6× under
186	Grandwood Park	2.3 pCi/L	0.6× under
187	Palatine	2.3 pCi/L	0.6× under
188	Pistakee Highlands	2.3 pCi/L	0.6× under
189	Pingree Grove	2.3 pCi/L	0.6× under
190	Wayne	2.3 pCi/L	0.6× under
191	Marion	2.2 pCi/L	0.6× under
192	Lemont	2.2 pCi/L	0.6× under
193	Belleville	2.2 pCi/L	0.6× under
194	Bethalto	2.2 pCi/L	0.6× under
195	Charleston	2.2 pCi/L	0.6× under
196	Libertyville	2.2 pCi/L	0.6× under
197	Inverness	2.2 pCi/L	0.5× under
198	Vernon Hills	2.2 pCi/L	0.5× under
199	Darien	2.2 pCi/L	0.5× under
200	Davis Junction	2.2 pCi/L	0.5× under
201	Warrenville	2.2 pCi/L	0.5× under
202	Arlington Heights	2.2 pCi/L	0.5× under
203	Buffalo Grove	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	Woodstock	2.1 pCi/L	0.5× under
207	East Moline	2.1 pCi/L	0.5× under
208	Villa Park	2.1 pCi/L	0.5× under
209	Goodings Grove	2.1 pCi/L	0.5× under
210	Rockton	2.1 pCi/L	0.5× under
211	West Peoria	2.1 pCi/L	0.5× under
212	Westmont	2.1 pCi/L	0.5× under
213	Hawthorn Woods	2.1 pCi/L	0.5× under
214	Morton Grove	2.1 pCi/L	0.5× under
215	Round Lake Heights	2.1 pCi/L	0.5× under
216	Evergreen Park	2.1 pCi/L	0.5× under
217	Gilberts	2.1 pCi/L	0.5× under
218	Wood Dale	2.1 pCi/L	0.5× under
219	Berwyn	2.1 pCi/L	0.5× under
220	Lakewood	2.1 pCi/L	0.5× under
221	Antioch	2.1 pCi/L	0.5× under
222	Collinsville	2.1 pCi/L	0.5× under
223	Poplar Grove	2.1 pCi/L	0.5× under
224	Lake in the Hills	2.0 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	Clarendon Hills	2.0 pCi/L	0.5× under
228	Glendale Heights	2.0 pCi/L	0.5× under
229	Des Plaines	2.0 pCi/L	0.5× under
230	Northbrook	2.0 pCi/L	0.5× under
231	Barrington	2.0 pCi/L	0.5× under
232	Marengo	2.0 pCi/L	0.5× under
233	Braidwood	2.0 pCi/L	0.5× under
234	Bloomingdale	2.0 pCi/L	0.5× under
235	Fox Lake	2.0 pCi/L	0.5× under
236	Frankfort Square	1.9 pCi/L	0.5× under
237	Knollwood	1.9 pCi/L	0.5× under
238	Zion	1.9 pCi/L	0.5× under
239	Highland Park	1.9 pCi/L	0.5× under
240	La Grange	1.9 pCi/L	0.5× under
241	Palos Hills	1.9 pCi/L	0.5× under
242	Germantown Hills	1.9 pCi/L	0.5× under
243	Brookfield	1.9 pCi/L	0.5× under
244	Lake of the Woods	1.9 pCi/L	0.5× under
245	Winnetka	1.9 pCi/L	0.5× under
246	Countryside	1.9 pCi/L	0.5× under
247	Flossmoor	1.9 pCi/L	0.5× under
248	Frankfort	1.9 pCi/L	0.5× under
249	Mahomet	1.9 pCi/L	0.5× under
250	Oak Park	1.9 pCi/L	0.5× under
251	Park Ridge	1.8 pCi/L	0.5× under
252	Wheeling	1.8 pCi/L	0.5× under
253	Oakbrook Terrace	1.8 pCi/L	0.5× under
254	Forest Park	1.8 pCi/L	0.5× under
255	Hinckley	1.8 pCi/L	0.5× under
256	Lake Zurich	1.8 pCi/L	0.5× under
257	Orland Hills	1.8 pCi/L	0.5× under
258	Cicero	1.8 pCi/L	0.4× under
259	Long Lake	1.8 pCi/L	0.4× under
260	Oakwood Hills	1.8 pCi/L	0.4× under
261	Merrionette Park	1.8 pCi/L	0.4× under
262	Hoffman Estates	1.8 pCi/L	0.4× under
263	Willow Springs	1.8 pCi/L	0.4× under
264	Twin Grove	1.7 pCi/L	0.4× under
265	Oak Brook	1.7 pCi/L	0.4× under
266	Oak Forest	1.7 pCi/L	0.4× under
267	Wasco	1.7 pCi/L	0.4× under
268	Bull Valley	1.7 pCi/L	0.4× under
269	Sherman	1.7 pCi/L	0.4× under
270	Paris	1.7 pCi/L	0.4× under
271	Bannockburn	1.6 pCi/L	0.4× under
272	Hometown	1.6 pCi/L	0.4× under
273	Hinsdale	1.6 pCi/L	0.4× under
274	Minooka	1.6 pCi/L	0.4× under
275	North Peoria	1.6 pCi/L	0.4× under
276	Hickory Hills	1.6 pCi/L	0.4× under
277	Highwood	1.6 pCi/L	0.4× under
278	Niles	1.6 pCi/L	0.4× under
279	Chillicothe	1.6 pCi/L	0.4× under
280	Carbondale	1.6 pCi/L	0.4× under
281	Deerfield	1.6 pCi/L	0.4× under
282	Lake Forest	1.6 pCi/L	0.4× under
283	Elk Grove Village	1.6 pCi/L	0.4× under
284	Joliet	1.6 pCi/L	0.4× under
285	Glencoe	1.5 pCi/L	0.4× under
286	Hanna City	1.4 pCi/L	0.4× under
287	Sandwich	1.4 pCi/L	0.4× under
288	Bensenville	1.4 pCi/L	0.4× under
289	Chatham	1.3 pCi/L	0.3× under
290	Harwood Heights	1.3 pCi/L	0.3× under
291	Wilmette	1.3 pCi/L	0.3× under
292	Lincolnwood	1.3 pCi/L	0.3× under
293	Riverside	1.3 pCi/L	0.3× under
294	Tinley Park	1.3 pCi/L	0.3× under
295	Norridge	1.2 pCi/L	0.3× under
296	Glen Carbon	1.2 pCi/L	0.3× under
297	Elmwood Park	1.2 pCi/L	0.3× under
298	Saint Joseph	1.2 pCi/L	0.3× under
299	Westchester	1.2 pCi/L	0.3× under
300	Stickney	1.1 pCi/L	0.3× under
301	Oak Lawn	1.1 pCi/L	0.3× under
302	Burbank	1.1 pCi/L	0.3× under
303	Homewood	1.1 pCi/L	0.3× under
304	Tower Lake	1.1 pCi/L	0.3× under
305	Skokie	1.0 pCi/L	0.3× under
306	Caseyville	0.9 pCi/L	0.2× under
307	Chicago	0.8 pCi/L	0.2× under
308	Grandview	0.7 pCi/L	0.2× under
309	Kenilworth	0.7 pCi/L	0.2× under
310	Evanston	0.6 pCi/L	0.1× under

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