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 271 cities.

Updated August 16, 2026

Highest city

9.3pCi/L

Milan

Illinois city average

2.7pCi/L

across 271 cities

Above action level

31/ 271

cities

Illinois Cities Ranked by Indoor Radon Levels
#	Location	Avg level	Monitors	vs action level
1	Milan	9.3 pCi/L	11	2.3× over
2	Godfrey	8.2 pCi/L	8	2.0× over
3	Crystal Lawns	7.5 pCi/L	17	1.9× over
4	Palos Park	7.5 pCi/L	12	1.9× over
5	Ingalls Park	6.9 pCi/L	10	1.7× over
6	Canton	6.7 pCi/L	6	1.7× over
7	Fairbury	6.6 pCi/L	6	1.6× over
8	Mattoon	6.4 pCi/L	6	1.6× over
9	Venetian Village	6.0 pCi/L	6	1.5× over
10	Mackinaw	5.9 pCi/L	6	1.5× over
11	Coal Valley	5.7 pCi/L	8	1.4× over
12	Jerome	5.1 pCi/L	22	1.3× over
13	Hampshire	5.0 pCi/L	12	1.3× over
14	Sugar Grove	4.9 pCi/L	10	1.2× over
15	Cherry Valley	4.9 pCi/L	16	1.2× over
16	Springfield	4.8 pCi/L	6	1.2× over
17	Columbia	4.8 pCi/L	19	1.2× over
18	Port Byron	4.7 pCi/L	11	1.2× over
19	Winnebago	4.6 pCi/L	9	1.2× over
20	Sterling	4.5 pCi/L	6	1.1× over
21	Elgin	4.5 pCi/L	50	1.1× over
22	Wauconda	4.4 pCi/L	21	1.1× over
23	Lebanon	4.4 pCi/L	8	1.1× over
24	Limestone	4.3 pCi/L	12	1.1× over
25	DeKalb	4.3 pCi/L	8	1.1× over
26	Jacksonville	4.2 pCi/L	9	1.0× over
27	Bolingbrook	4.2 pCi/L	38	1.0× over
28	Carpentersville	4.1 pCi/L	8	1.0× over
29	South Elgin	4.0 pCi/L	28	1.0× over
30	Lake Villa	4.0 pCi/L	12	1.0× over
31	Spring Grove	4.0 pCi/L	13	1.0× over
✓ Below EPA action level (4 pCi/L)
32	Lindenhurst	4.0 pCi/L	9	1.0× under
33	Machesney Park	4.0 pCi/L	21	1.0× under
34	Peoria	3.9 pCi/L	9	1.0× under
35	Montgomery	3.9 pCi/L	15	1.0× under
36	Macomb	3.8 pCi/L	8	1.0× under
37	Rochester	3.8 pCi/L	8	0.9× under
38	Elburn	3.7 pCi/L	21	0.9× under
39	Metamora	3.7 pCi/L	11	0.9× under
40	Moline	3.7 pCi/L	21	0.9× under
41	Cuba	3.6 pCi/L	14	0.9× under
42	Lombard	3.6 pCi/L	55	0.9× under
43	Pekin	3.6 pCi/L	12	0.9× under
44	Crystal Lake	3.6 pCi/L	39	0.9× under
45	Grayslake	3.5 pCi/L	43	0.9× under
46	Morton	3.5 pCi/L	21	0.9× under
47	Urbana	3.5 pCi/L	32	0.9× under
48	Bloomington	3.4 pCi/L	38	0.9× under
49	Channahon	3.4 pCi/L	17	0.9× under
50	Fairview Heights	3.4 pCi/L	15	0.9× under
51	Bourbonnais	3.4 pCi/L	7	0.8× under
52	Galena	3.4 pCi/L	12	0.8× under
53	Lockport	3.4 pCi/L	18	0.8× under
54	Morris	3.4 pCi/L	12	0.8× under
55	Schaumburg	3.4 pCi/L	65	0.8× under
56	Indian Head Park	3.4 pCi/L	16	0.8× under
57	Romeoville	3.3 pCi/L	32	0.8× under
58	Richmond	3.3 pCi/L	6	0.8× under
59	Glen Ellyn	3.3 pCi/L	70	0.8× under
60	Batavia	3.3 pCi/L	55	0.8× under
61	Round Lake	3.3 pCi/L	13	0.8× under
62	O'Fallon	3.2 pCi/L	30	0.8× under
63	Prospect Heights	3.2 pCi/L	28	0.8× under
64	Shorewood	3.2 pCi/L	56	0.8× under
65	Maryville	3.1 pCi/L	13	0.8× under
66	Wonder Lake	3.1 pCi/L	20	0.8× under
67	Freeport	3.1 pCi/L	10	0.8× under
68	Fox Lake Hills	3.1 pCi/L	11	0.8× under
69	Waukegan	3.1 pCi/L	10	0.8× under
70	Hampton	3.1 pCi/L	24	0.8× under
71	Roselle	3.1 pCi/L	31	0.8× under
72	Roscoe	3.1 pCi/L	21	0.8× under
73	Le Roy	3.0 pCi/L	6	0.8× under
74	Forest Lake	3.0 pCi/L	15	0.8× under
75	Lincolnshire	3.0 pCi/L	41	0.8× under
76	North Aurora	3.0 pCi/L	39	0.8× under
77	Swansea	3.0 pCi/L	13	0.8× under
78	La Grange Park	3.0 pCi/L	15	0.8× under
79	South Beloit	3.0 pCi/L	8	0.8× under
80	Sleepy Hollow	3.0 pCi/L	7	0.8× under
81	Carol Stream	3.0 pCi/L	41	0.7× under
82	New Lenox	3.0 pCi/L	46	0.7× under
83	Lake Bluff	3.0 pCi/L	15	0.7× under
84	Waterloo	3.0 pCi/L	11	0.7× under
85	Edwardsville	3.0 pCi/L	31	0.7× under
86	Saint Charles	3.0 pCi/L	38	0.7× under
87	Troy	2.9 pCi/L	19	0.7× under
88	West Chicago	2.9 pCi/L	24	0.7× under
89	Farmington	2.9 pCi/L	25	0.7× under
90	Shiloh	2.9 pCi/L	23	0.7× under
91	Boulder Hill	2.9 pCi/L	33	0.7× under
92	Bradley	2.9 pCi/L	9	0.7× under
93	Deer Park	2.9 pCi/L	24	0.7× under
94	Wheaton	2.9 pCi/L	72	0.7× under
95	Plano	2.9 pCi/L	10	0.7× under
96	Quincy	2.9 pCi/L	22	0.7× under
97	Decatur	2.9 pCi/L	9	0.7× under
98	Addison	2.8 pCi/L	20	0.7× under
99	Crest Hill	2.8 pCi/L	8	0.7× under
100	River Forest	2.8 pCi/L	29	0.7× under
101	Bartlett	2.8 pCi/L	36	0.7× under
102	Northfield	2.8 pCi/L	19	0.7× under
103	Belvidere	2.8 pCi/L	19	0.7× under
104	Burr Ridge	2.8 pCi/L	23	0.7× under
105	Lynwood	2.8 pCi/L	32	0.7× under
106	Winfield	2.8 pCi/L	29	0.7× under
107	Prairie Grove	2.7 pCi/L	9	0.7× under
108	Yorkville	2.7 pCi/L	28	0.7× under
109	Alton	2.7 pCi/L	6	0.7× under
110	Loves Park	2.7 pCi/L	12	0.7× under
111	Peoria Heights	2.7 pCi/L	18	0.7× under
112	Barrington Hills	2.7 pCi/L	10	0.7× under
113	Mundelein	2.7 pCi/L	45	0.7× under
114	Normal	2.7 pCi/L	49	0.7× under
115	Dunlap	2.7 pCi/L	41	0.7× under
116	Manhattan	2.7 pCi/L	14	0.7× under
117	Rolling Meadows	2.7 pCi/L	22	0.7× under
118	Homer Glen	2.6 pCi/L	40	0.7× under
119	Geneva	2.6 pCi/L	55	0.7× under
120	Savoy	2.6 pCi/L	31	0.7× under
121	Champaign	2.6 pCi/L	48	0.7× under
122	Willowbrook	2.6 pCi/L	17	0.7× under
123	Winthrop Harbor	2.6 pCi/L	8	0.7× under
124	Downers Grove	2.6 pCi/L	85	0.6× under
125	Village of Campton Hills	2.6 pCi/L	21	0.6× under
126	Mokena	2.6 pCi/L	47	0.6× under
127	Rockford	2.6 pCi/L	39	0.6× under
128	Ottawa	2.6 pCi/L	28	0.6× under
129	Fox River Grove	2.5 pCi/L	13	0.6× under
130	Lisle	2.5 pCi/L	96	0.6× under
131	Woodridge	2.5 pCi/L	50	0.6× under
132	Leland Grove	2.5 pCi/L	22	0.6× under
133	Algonquin	2.5 pCi/L	41	0.6× under
134	McHenry	2.5 pCi/L	21	0.6× under
135	Peotone	2.5 pCi/L	6	0.6× under
136	Riverwoods	2.5 pCi/L	21	0.6× under
137	Wadsworth	2.5 pCi/L	9	0.6× under
138	Itasca	2.4 pCi/L	27	0.6× under
139	Long Grove	2.4 pCi/L	28	0.6× under
140	Sycamore	2.4 pCi/L	17	0.6× under
141	Hanover Park	2.4 pCi/L	28	0.6× under
142	Gages Lake	2.4 pCi/L	23	0.6× under
143	Naperville	2.4 pCi/L	276	0.6× under
144	Plainfield	2.4 pCi/L	205	0.6× under
145	Glenview	2.4 pCi/L	72	0.6× under
146	Aurora	2.4 pCi/L	76	0.6× under
147	Elmhurst	2.4 pCi/L	72	0.6× under
148	Gurnee	2.4 pCi/L	29	0.6× under
149	Western Springs	2.4 pCi/L	36	0.6× under
150	Mount Prospect	2.3 pCi/L	54	0.6× under
151	Streamwood	2.3 pCi/L	31	0.6× under
152	Fulton	2.3 pCi/L	6	0.6× under
153	Huntley	2.3 pCi/L	23	0.6× under
154	Orland Park	2.3 pCi/L	39	0.6× under
155	Green Oaks	2.3 pCi/L	10	0.6× under
156	Palos Heights	2.3 pCi/L	10	0.6× under
157	Belleville	2.3 pCi/L	11	0.6× under
158	Oswego	2.3 pCi/L	38	0.6× under
159	Berwyn	2.3 pCi/L	15	0.6× under
160	Kildeer	2.3 pCi/L	29	0.6× under
161	Pingree Grove	2.3 pCi/L	36	0.6× under
162	Cary	2.3 pCi/L	18	0.6× under
163	Palatine	2.3 pCi/L	84	0.6× under
164	Grandwood Park	2.3 pCi/L	9	0.6× under
165	Lemont	2.3 pCi/L	42	0.6× under
166	Pistakee Highlands	2.3 pCi/L	7	0.6× under
167	Wayne	2.3 pCi/L	21	0.6× under
168	Warrenville	2.2 pCi/L	87	0.6× under
169	Charleston	2.2 pCi/L	6	0.6× under
170	Libertyville	2.2 pCi/L	88	0.6× under
171	Vernon Hills	2.2 pCi/L	54	0.6× under
172	Inverness	2.2 pCi/L	25	0.5× under
173	Morton Grove	2.2 pCi/L	20	0.5× under
174	Villa Park	2.2 pCi/L	23	0.5× under
175	Woodstock	2.2 pCi/L	29	0.5× under
176	Arlington Heights	2.2 pCi/L	99	0.5× under
177	Buffalo Grove	2.2 pCi/L	66	0.5× under
178	Darien	2.2 pCi/L	64	0.5× under
179	Washington	2.2 pCi/L	15	0.5× under
180	Fairfield	2.1 pCi/L	13	0.5× under
181	East Moline	2.1 pCi/L	12	0.5× under
182	Rockton	2.1 pCi/L	9	0.5× under
183	West Peoria	2.1 pCi/L	8	0.5× under
184	Hawthorn Woods	2.1 pCi/L	25	0.5× under
185	Round Lake Heights	2.1 pCi/L	7	0.5× under
186	Evergreen Park	2.1 pCi/L	21	0.5× under
187	Gilberts	2.1 pCi/L	15	0.5× under
188	Wood Dale	2.1 pCi/L	10	0.5× under
189	Collinsville	2.1 pCi/L	11	0.5× under
190	South Barrington	2.1 pCi/L	50	0.5× under
191	Antioch	2.1 pCi/L	19	0.5× under
192	Lake in the Hills	2.1 pCi/L	61	0.5× under
193	Lakewood	2.1 pCi/L	52	0.5× under
194	Poplar Grove	2.1 pCi/L	8	0.5× under
195	Bethalto	2.0 pCi/L	9	0.5× under
196	Des Plaines	2.0 pCi/L	38	0.5× under
197	Clarendon Hills	2.0 pCi/L	19	0.5× under
198	Westmont	2.0 pCi/L	23	0.5× under
199	Brookfield	2.0 pCi/L	19	0.5× under
200	Barrington	2.0 pCi/L	26	0.5× under
201	Glendale Heights	2.0 pCi/L	12	0.5× under
202	Goodings Grove	2.0 pCi/L	23	0.5× under
203	Marengo	2.0 pCi/L	9	0.5× under
204	Northbrook	2.0 pCi/L	107	0.5× under
205	Fox Lake	2.0 pCi/L	8	0.5× under
206	Lake of the Woods	1.9 pCi/L	6	0.5× under
207	Mahomet	1.9 pCi/L	9	0.5× under
208	Palos Hills	1.9 pCi/L	11	0.5× under
209	Frankfort Square	1.9 pCi/L	17	0.5× under
210	Knollwood	1.9 pCi/L	27	0.5× under
211	Zion	1.9 pCi/L	6	0.5× under
212	Bloomingdale	1.9 pCi/L	23	0.5× under
213	Highland Park	1.9 pCi/L	50	0.5× under
214	Germantown Hills	1.9 pCi/L	18	0.5× under
215	Cicero	1.9 pCi/L	13	0.5× under
216	Oak Park	1.9 pCi/L	115	0.5× under
217	Countryside	1.9 pCi/L	6	0.5× under
218	Forest Park	1.9 pCi/L	26	0.5× under
219	La Grange	1.9 pCi/L	38	0.5× under
220	Lake Zurich	1.9 pCi/L	49	0.5× under
221	Long Lake	1.9 pCi/L	8	0.5× under
222	Oakbrook Terrace	1.9 pCi/L	22	0.5× under
223	Wheeling	1.8 pCi/L	14	0.5× under
224	Hinckley	1.8 pCi/L	10	0.5× under
225	Park Ridge	1.8 pCi/L	51	0.5× under
226	Bull Valley	1.8 pCi/L	11	0.5× under
227	Orland Hills	1.8 pCi/L	23	0.5× under
228	Frankfort	1.8 pCi/L	34	0.5× under
229	Oakwood Hills	1.8 pCi/L	10	0.4× under
230	Merrionette Park	1.8 pCi/L	11	0.4× under
231	Hoffman Estates	1.8 pCi/L	32	0.4× under
232	Willow Springs	1.8 pCi/L	6	0.4× under
233	Twin Grove	1.7 pCi/L	8	0.4× under
234	Oak Brook	1.7 pCi/L	13	0.4× under
235	Oak Forest	1.7 pCi/L	6	0.4× under
236	Wasco	1.7 pCi/L	14	0.4× under
237	Sherman	1.7 pCi/L	9	0.4× under
238	Hometown	1.7 pCi/L	13	0.4× under
239	Bannockburn	1.7 pCi/L	26	0.4× under
240	Hinsdale	1.7 pCi/L	45	0.4× under
241	Minooka	1.6 pCi/L	15	0.4× under
242	North Peoria	1.6 pCi/L	9	0.4× under
243	Niles	1.6 pCi/L	25	0.4× under
244	Hickory Hills	1.6 pCi/L	7	0.4× under
245	Highwood	1.6 pCi/L	15	0.4× under
246	Deerfield	1.6 pCi/L	50	0.4× under
247	Lake Forest	1.6 pCi/L	38	0.4× under
248	Carbondale	1.6 pCi/L	10	0.4× under
249	Winnetka	1.5 pCi/L	29	0.4× under
250	Elk Grove Village	1.5 pCi/L	28	0.4× under
251	Sandwich	1.5 pCi/L	9	0.4× under
252	Glencoe	1.5 pCi/L	36	0.4× under
253	Chatham	1.3 pCi/L	11	0.3× under
254	Wilmette	1.3 pCi/L	47	0.3× under
255	Lincolnwood	1.3 pCi/L	245	0.3× under
256	Harwood Heights	1.3 pCi/L	51	0.3× under
257	Riverside	1.3 pCi/L	19	0.3× under
258	Tinley Park	1.3 pCi/L	15	0.3× under
259	Glen Carbon	1.3 pCi/L	9	0.3× under
260	Norridge	1.2 pCi/L	12	0.3× under
261	Elmwood Park	1.2 pCi/L	17	0.3× under
262	Westchester	1.2 pCi/L	8	0.3× under
263	Stickney	1.1 pCi/L	7	0.3× under
264	Oak Lawn	1.1 pCi/L	17	0.3× under
265	Tower Lake	1.1 pCi/L	13	0.3× under
266	Burbank	1.1 pCi/L	12	0.3× under
267	Homewood	1.0 pCi/L	8	0.3× under
268	Skokie	1.0 pCi/L	27	0.3× under
269	Chicago	0.8 pCi/L	670	0.2× under
270	Kenilworth	0.8 pCi/L	11	0.2× under
271	Evanston	0.6 pCi/L	106	0.1× under

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