Most Flood-Prone Counties in Illinois

Based on NOAA Storm Events Database records from 1996 to 2025, these are the Illinois counties with the most recorded flood events. Cook County tops the list with 390 events. The data includes river floods, flash floods, coastal flooding, and hurricane-related flooding.

Rank	County	Total Events	River Floods	Flash Floods
1	Cook County	390	206	184
2	White County	189	164	25
3	Alexander County	173	152	21
4	Will County	151	86	65
5	DuPage County	139	76	63
6	Jackson County	134	90	44
7	Gallatin County	118	96	22
8	Rock Island County	109	71	38
9	Wabash County	108	90	18
10	Franklin County	103	64	39
11	Pulaski County	93	79	14
12	Wayne County	91	55	36
13	Massac County	87	68	19
14	Lake County	80	33	47
15	Winnebago County	80	45	35
16	Hancock County	78	41	37
17	Sangamon County	78	13	65
18	LaSalle County	77	41	36
19	Effingham County	71	12	59
20	Champaign County	70	6	64
21	Clay County	65	8	57
22	Kane County	65	36	29
23	McDonough County	65	20	45
24	Williamson County	63	23	40
25	Shelby County	62	9	53
26	Saline County	61	18	43
27	Fulton County	60	10	50
28	Perry County	60	20	40
29	Pope County	58	40	18
30	Vermilion County	58	5	53
31	Henry County	56	20	36
32	Jo Daviess County	55	14	41
33	Kankakee County	53	29	24
34	Whiteside County	53	30	23
35	Henderson County	53	34	19
36	Stephenson County	53	13	40
37	St. Clair County	52	8	44
38	Iroquois County	51	26	25
39	Christian County	51	5	46
40	Crawford County	51	8	43
41	Coles County	50	9	41
42	Logan County	48	5	43
43	Mercer County	48	35	13
44	Union County	48	22	26
45	Jasper County	47	7	40
46	Lawrence County	47	8	39
47	Jefferson County	46	12	34
48	Hamilton County	46	15	31
49	Peoria County	46	7	39
50	Livingston County	45	25	20
51	McLean County	45	7	38
52	Carroll County	44	14	30
53	Macon County	44	2	42
54	Ogle County	44	18	26
55	Tazewell County	43	7	36
56	DeKalb County	42	15	27
57	Edgar County	42	5	37
58	Knox County	42	8	34
59	Morgan County	42	10	32
60	Woodford County	41	8	33
61	Grundy County	39	22	17
62	Clark County	38	7	31
63	Schuyler County	38	6	32
64	Scott County	38	7	31
65	Richland County	37	5	32
66	Cumberland County	36	7	29
67	Kendall County	36	16	20
68	McHenry County	36	19	17
69	Madison County	36	9	27
70	Douglas County	34	8	26
71	Ford County	34	17	17
72	Hardin County	33	21	12
73	Marion County	33	2	31
74	Adams County	32	7	25
75	Bureau County	31	5	26
76	Boone County	30	16	14
77	Marshall County	30	9	21
78	Cass County	29	4	25
79	Moultrie County	29	6	23
80	Lee County	28	10	18
81	Macoupin County	28	1	27
82	Edwards County	27	11	16
83	Jersey County	26	10	16
84	Warren County	26	7	19
85	Menard County	25	2	23
86	Randolph County	25	6	19
87	Monroe County	25	6	19
88	Johnson County	24	10	14
89	Fayette County	23	2	21
90	Piatt County	23	3	20
91	Stark County	23	5	18
92	Calhoun County	21	8	13
93	Mason County	21	3	18
94	Montgomery County	21	1	20
95	Bond County	21	2	19
96	Clinton County	21	1	20
97	Pike County	21	10	11
98	De Witt County	20	2	18
99	Washington County	16	2	14
100	Brown County	15	4	11
101	Greene County	15	3	12
102	Putnam County	14	3	11

Source: NOAA Storm Events Database (1996–2025).

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