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 9.3 pCi/L, based on Airthings measurements across 302 cities.

Updated August 30, 2026

Highest city

9.3pCi/L

Milan

Illinois city average

2.8pCi/L

across 302 cities

Above action level

40/ 302

cities

Illinois Cities Ranked by Indoor Radon Levels
#	Location	Avg level	vs action level
1	Milan	9.3 pCi/L	2.3× over
2	Godfrey	8.2 pCi/L	2.0× over
3	Crystal Lawns	7.5 pCi/L	1.9× over
4	Palos Park	7.5 pCi/L	1.9× over
5	Galesburg	7.5 pCi/L	1.9× 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	Venetian Village	6.0 pCi/L	1.5× over
13	Beach Park	6.0 pCi/L	1.5× over
14	Mackinaw	5.9 pCi/L	1.5× over
15	Coal Valley	5.7 pCi/L	1.4× over
16	Jerome	5.1 pCi/L	1.3× over
17	Marseilles	5.1 pCi/L	1.3× over
18	Byron	5.0 pCi/L	1.3× over
19	Rochelle	5.0 pCi/L	1.3× over
20	Hampshire	5.0 pCi/L	1.3× over
21	Sugar Grove	4.9 pCi/L	1.2× over
22	Cherry Valley	4.9 pCi/L	1.2× over
23	Springfield	4.8 pCi/L	1.2× over
24	Bellevue	4.8 pCi/L	1.2× over
25	Columbia	4.8 pCi/L	1.2× over
26	Port Byron	4.7 pCi/L	1.2× over
27	Winnebago	4.6 pCi/L	1.2× over
28	Sterling	4.5 pCi/L	1.1× over
29	Elgin	4.5 pCi/L	1.1× over
30	Sheridan	4.4 pCi/L	1.1× over
31	Wauconda	4.4 pCi/L	1.1× over
32	Lebanon	4.4 pCi/L	1.1× over
33	Limestone	4.3 pCi/L	1.1× over
34	DeKalb	4.3 pCi/L	1.1× over
35	Jacksonville	4.2 pCi/L	1.0× over
36	Bolingbrook	4.2 pCi/L	1.0× over
37	Carpentersville	4.1 pCi/L	1.0× over
38	South Elgin	4.0 pCi/L	1.0× over
39	Lake Villa	4.0 pCi/L	1.0× over
40	Spring Grove	4.0 pCi/L	1.0× over
✓ Below EPA action level (4 pCi/L)
41	Lindenhurst	4.0 pCi/L	1.0× under
42	Paxton	4.0 pCi/L	1.0× under
43	East Hazel Crest	4.0 pCi/L	1.0× under
44	Hillside	4.0 pCi/L	1.0× under
45	Machesney Park	4.0 pCi/L	1.0× under
46	Monee	4.0 pCi/L	1.0× under
47	Peoria	3.9 pCi/L	1.0× under
48	Montgomery	3.9 pCi/L	1.0× under
49	Macomb	3.8 pCi/L	1.0× under
50	Rochester	3.8 pCi/L	0.9× under
51	Elburn	3.7 pCi/L	0.9× under
52	Metamora	3.7 pCi/L	0.9× under
53	Moline	3.7 pCi/L	0.9× under
54	Cuba	3.6 pCi/L	0.9× under
55	Lombard	3.6 pCi/L	0.9× under
56	Pekin	3.6 pCi/L	0.9× under
57	Grayslake	3.5 pCi/L	0.9× under
58	Morton	3.5 pCi/L	0.9× under
59	Dixon	3.5 pCi/L	0.9× under
60	Urbana	3.5 pCi/L	0.9× under
61	Crystal Lake	3.5 pCi/L	0.9× under
62	Bloomington	3.4 pCi/L	0.9× under
63	Channahon	3.4 pCi/L	0.9× under
64	Fairview Heights	3.4 pCi/L	0.9× under
65	Bourbonnais	3.4 pCi/L	0.8× under
66	Galena	3.4 pCi/L	0.8× under
67	Lockport	3.4 pCi/L	0.8× under
68	Morris	3.4 pCi/L	0.8× under
69	Schaumburg	3.4 pCi/L	0.8× under
70	Indian Head Park	3.4 pCi/L	0.8× under
71	Romeoville	3.3 pCi/L	0.8× under
72	Richmond	3.3 pCi/L	0.8× under
73	Glen Ellyn	3.3 pCi/L	0.8× under
74	Batavia	3.3 pCi/L	0.8× under
75	Round Lake	3.3 pCi/L	0.8× under
76	O'Fallon	3.2 pCi/L	0.8× under
77	Prospect Heights	3.2 pCi/L	0.8× under
78	Shorewood	3.2 pCi/L	0.8× under
79	Lake Barrington	3.2 pCi/L	0.8× under
80	Maryville	3.1 pCi/L	0.8× under
81	Wonder Lake	3.1 pCi/L	0.8× under
82	Freeport	3.1 pCi/L	0.8× under
83	Fox Lake Hills	3.1 pCi/L	0.8× under
84	Waukegan	3.1 pCi/L	0.8× under
85	Hampton	3.1 pCi/L	0.8× under
86	Roselle	3.1 pCi/L	0.8× under
87	Roscoe	3.1 pCi/L	0.8× under
88	Le Roy	3.0 pCi/L	0.8× under
89	Forest Lake	3.0 pCi/L	0.8× under
90	Forsyth	3.0 pCi/L	0.8× under
91	Lincolnshire	3.0 pCi/L	0.8× under
92	North Aurora	3.0 pCi/L	0.8× under
93	Swansea	3.0 pCi/L	0.8× under
94	La Grange Park	3.0 pCi/L	0.8× under
95	South Beloit	3.0 pCi/L	0.8× under
96	Sleepy Hollow	3.0 pCi/L	0.8× under
97	Carol Stream	3.0 pCi/L	0.7× under
98	New Lenox	3.0 pCi/L	0.7× under
99	Lake Bluff	3.0 pCi/L	0.7× under
100	Waterloo	3.0 pCi/L	0.7× under
101	Edwardsville	3.0 pCi/L	0.7× under
102	Murphysboro	3.0 pCi/L	0.7× under
103	Saint Charles	3.0 pCi/L	0.7× under
104	Troy	2.9 pCi/L	0.7× under
105	West Chicago	2.9 pCi/L	0.7× under
106	Calumet Park	2.9 pCi/L	0.7× under
107	Farmington	2.9 pCi/L	0.7× under
108	Shiloh	2.9 pCi/L	0.7× under
109	Boulder Hill	2.9 pCi/L	0.7× under
110	Bradley	2.9 pCi/L	0.7× under
111	Deer Park	2.9 pCi/L	0.7× under
112	Wheaton	2.9 pCi/L	0.7× under
113	Plano	2.9 pCi/L	0.7× under
114	Quincy	2.9 pCi/L	0.7× under
115	Decatur	2.9 pCi/L	0.7× under
116	Round Lake Beach	2.8 pCi/L	0.7× under
117	Addison	2.8 pCi/L	0.7× under
118	Crest Hill	2.8 pCi/L	0.7× under
119	River Forest	2.8 pCi/L	0.7× under
120	Bartlett	2.8 pCi/L	0.7× under
121	Northfield	2.8 pCi/L	0.7× under
122	Belvidere	2.8 pCi/L	0.7× under
123	Burr Ridge	2.8 pCi/L	0.7× under
124	Lynwood	2.8 pCi/L	0.7× under
125	Winfield	2.8 pCi/L	0.7× under
126	Prairie Grove	2.7 pCi/L	0.7× under
127	Yorkville	2.7 pCi/L	0.7× under
128	Alton	2.7 pCi/L	0.7× under
129	Loves Park	2.7 pCi/L	0.7× under
130	Minier	2.7 pCi/L	0.7× under
131	Peoria Heights	2.7 pCi/L	0.7× under
132	Barrington Hills	2.7 pCi/L	0.7× under
133	Mundelein	2.7 pCi/L	0.7× under
134	Normal	2.7 pCi/L	0.7× under
135	Dunlap	2.7 pCi/L	0.7× under
136	Manhattan	2.7 pCi/L	0.7× under
137	Rolling Meadows	2.7 pCi/L	0.7× under
138	Homer Glen	2.6 pCi/L	0.7× under
139	Geneva	2.6 pCi/L	0.7× under
140	Savoy	2.6 pCi/L	0.7× under
141	Champaign	2.6 pCi/L	0.7× under
142	Willowbrook	2.6 pCi/L	0.7× under
143	Winthrop Harbor	2.6 pCi/L	0.7× under
144	Downers Grove	2.6 pCi/L	0.6× under
145	Village of Campton Hills	2.6 pCi/L	0.6× under
146	Rockford	2.6 pCi/L	0.6× under
147	Ottawa	2.6 pCi/L	0.6× under
148	Green Oaks	2.5 pCi/L	0.6× under
149	Mokena	2.5 pCi/L	0.6× under
150	Rosemont	2.5 pCi/L	0.6× under
151	Fox River Grove	2.5 pCi/L	0.6× under
152	Lisle	2.5 pCi/L	0.6× under
153	Woodridge	2.5 pCi/L	0.6× under
154	Leland Grove	2.5 pCi/L	0.6× under
155	Algonquin	2.5 pCi/L	0.6× under
156	McHenry	2.5 pCi/L	0.6× under
157	Peotone	2.5 pCi/L	0.6× under
158	Riverwoods	2.5 pCi/L	0.6× under
159	Wadsworth	2.5 pCi/L	0.6× under
160	Itasca	2.4 pCi/L	0.6× under
161	Mount Zion	2.4 pCi/L	0.6× under
162	Long Grove	2.4 pCi/L	0.6× under
163	Sycamore	2.4 pCi/L	0.6× under
164	Hanover Park	2.4 pCi/L	0.6× under
165	Gages Lake	2.4 pCi/L	0.6× under
166	Naperville	2.4 pCi/L	0.6× under
167	Plainfield	2.4 pCi/L	0.6× under
168	Glenview	2.4 pCi/L	0.6× under
169	Aurora	2.4 pCi/L	0.6× under
170	Elmhurst	2.4 pCi/L	0.6× under
171	Gurnee	2.4 pCi/L	0.6× under
172	Western Springs	2.4 pCi/L	0.6× under
173	Mount Prospect	2.3 pCi/L	0.6× under
174	Streamwood	2.3 pCi/L	0.6× under
175	Fulton	2.3 pCi/L	0.6× under
176	Huntley	2.3 pCi/L	0.6× under
177	Orland Park	2.3 pCi/L	0.6× under
178	Palos Heights	2.3 pCi/L	0.6× under
179	Davis Junction	2.3 pCi/L	0.6× under
180	Belleville	2.3 pCi/L	0.6× under
181	Oswego	2.3 pCi/L	0.6× under
182	Berwyn	2.3 pCi/L	0.6× under
183	Kildeer	2.3 pCi/L	0.6× under
184	Pingree Grove	2.3 pCi/L	0.6× under
185	Cary	2.3 pCi/L	0.6× under
186	Palatine	2.3 pCi/L	0.6× under
187	Grandwood Park	2.3 pCi/L	0.6× under
188	Lemont	2.3 pCi/L	0.6× under
189	Pistakee Highlands	2.3 pCi/L	0.6× under
190	Wayne	2.3 pCi/L	0.6× under
191	Charleston	2.2 pCi/L	0.6× under
192	Libertyville	2.2 pCi/L	0.6× under
193	Vernon Hills	2.2 pCi/L	0.6× under
194	Warrenville	2.2 pCi/L	0.6× under
195	Inverness	2.2 pCi/L	0.5× under
196	Morton Grove	2.2 pCi/L	0.5× under
197	Villa Park	2.2 pCi/L	0.5× under
198	Woodstock	2.2 pCi/L	0.5× under
199	Arlington Heights	2.2 pCi/L	0.5× under
200	Buffalo Grove	2.2 pCi/L	0.5× under
201	Darien	2.2 pCi/L	0.5× under
202	Washington	2.2 pCi/L	0.5× under
203	Fairfield	2.1 pCi/L	0.5× under
204	East Moline	2.1 pCi/L	0.5× under
205	Rockton	2.1 pCi/L	0.5× under
206	West Peoria	2.1 pCi/L	0.5× under
207	Hawthorn Woods	2.1 pCi/L	0.5× under
208	Round Lake Heights	2.1 pCi/L	0.5× under
209	Evergreen Park	2.1 pCi/L	0.5× under
210	Gilberts	2.1 pCi/L	0.5× under
211	Wood Dale	2.1 pCi/L	0.5× under
212	Braidwood	2.1 pCi/L	0.5× under
213	Collinsville	2.1 pCi/L	0.5× under
214	South Barrington	2.1 pCi/L	0.5× under
215	Antioch	2.1 pCi/L	0.5× under
216	Lake in the Hills	2.1 pCi/L	0.5× under
217	Lakewood	2.1 pCi/L	0.5× under
218	Poplar Grove	2.1 pCi/L	0.5× under
219	Round Lake Park	2.0 pCi/L	0.5× under
220	Bethalto	2.0 pCi/L	0.5× under
221	Clarendon Hills	2.0 pCi/L	0.5× under
222	Westmont	2.0 pCi/L	0.5× under
223	Brookfield	2.0 pCi/L	0.5× under
224	Glendale Heights	2.0 pCi/L	0.5× under
225	Barrington	2.0 pCi/L	0.5× under
226	Goodings Grove	2.0 pCi/L	0.5× under
227	Des Plaines	2.0 pCi/L	0.5× under
228	Marengo	2.0 pCi/L	0.5× under
229	Northbrook	2.0 pCi/L	0.5× under
230	Fox Lake	2.0 pCi/L	0.5× under
231	Lake of the Woods	1.9 pCi/L	0.5× under
232	Mahomet	1.9 pCi/L	0.5× under
233	Palos Hills	1.9 pCi/L	0.5× under
234	Winnetka	1.9 pCi/L	0.5× under
235	Frankfort Square	1.9 pCi/L	0.5× under
236	Knollwood	1.9 pCi/L	0.5× under
237	Zion	1.9 pCi/L	0.5× under
238	Bloomingdale	1.9 pCi/L	0.5× under
239	Highland Park	1.9 pCi/L	0.5× under
240	Germantown Hills	1.9 pCi/L	0.5× under
241	Cicero	1.9 pCi/L	0.5× under
242	Countryside	1.9 pCi/L	0.5× under
243	Flossmoor	1.9 pCi/L	0.5× under
244	Forest Park	1.9 pCi/L	0.5× under
245	Oak Park	1.9 pCi/L	0.5× under
246	La Grange	1.9 pCi/L	0.5× under
247	Lake Zurich	1.9 pCi/L	0.5× under
248	Long Lake	1.9 pCi/L	0.5× under
249	Oakbrook Terrace	1.9 pCi/L	0.5× under
250	Park Ridge	1.9 pCi/L	0.5× under
251	Wheeling	1.8 pCi/L	0.5× under
252	Hinckley	1.8 pCi/L	0.5× under
253	Orland Hills	1.8 pCi/L	0.5× under
254	Frankfort	1.8 pCi/L	0.5× under
255	Oakwood Hills	1.8 pCi/L	0.4× under
256	Merrionette Park	1.8 pCi/L	0.4× under
257	Hoffman Estates	1.8 pCi/L	0.4× under
258	Willow Springs	1.8 pCi/L	0.4× under
259	Twin Grove	1.7 pCi/L	0.4× under
260	Oak Brook	1.7 pCi/L	0.4× under
261	Oak Forest	1.7 pCi/L	0.4× under
262	Wasco	1.7 pCi/L	0.4× under
263	Bull Valley	1.7 pCi/L	0.4× under
264	Sherman	1.7 pCi/L	0.4× under
265	Hometown	1.7 pCi/L	0.4× under
266	Paris	1.7 pCi/L	0.4× under
267	Bannockburn	1.7 pCi/L	0.4× under
268	Hinsdale	1.7 pCi/L	0.4× under
269	Minooka	1.6 pCi/L	0.4× under
270	North Peoria	1.6 pCi/L	0.4× under
271	Hickory Hills	1.6 pCi/L	0.4× under
272	Highwood	1.6 pCi/L	0.4× under
273	Niles	1.6 pCi/L	0.4× under
274	Deerfield	1.6 pCi/L	0.4× under
275	Carbondale	1.6 pCi/L	0.4× under
276	Lake Forest	1.6 pCi/L	0.4× under
277	Elk Grove Village	1.5 pCi/L	0.4× under
278	Sandwich	1.5 pCi/L	0.4× under
279	Glencoe	1.5 pCi/L	0.4× under
280	Hanna City	1.4 pCi/L	0.4× under
281	Bensenville	1.4 pCi/L	0.4× under
282	Chatham	1.3 pCi/L	0.3× under
283	Wilmette	1.3 pCi/L	0.3× under
284	Lincolnwood	1.3 pCi/L	0.3× under
285	Harwood Heights	1.3 pCi/L	0.3× under
286	Riverside	1.3 pCi/L	0.3× under
287	Tinley Park	1.3 pCi/L	0.3× under
288	Glen Carbon	1.3 pCi/L	0.3× under
289	Norridge	1.2 pCi/L	0.3× under
290	Elmwood Park	1.2 pCi/L	0.3× under
291	Westchester	1.2 pCi/L	0.3× under
292	Stickney	1.1 pCi/L	0.3× under
293	Oak Lawn	1.1 pCi/L	0.3× under
294	Tower Lake	1.1 pCi/L	0.3× under
295	Burbank	1.1 pCi/L	0.3× under
296	Homewood	1.0 pCi/L	0.3× under
297	Joliet	1.0 pCi/L	0.3× under
298	Skokie	1.0 pCi/L	0.3× under
299	Caseyville	0.9 pCi/L	0.2× under
300	Chicago	0.8 pCi/L	0.2× under
301	Kenilworth	0.8 pCi/L	0.2× under
302	Evanston	0.6 pCi/L	0.1× under

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