Most Flood-Prone Counties in Iowa

Based on NOAA Storm Events Database records from 1996 to 2025, these are the Iowa counties with the most recorded flood events. Polk County tops the list with 295 events. The data includes river floods, flash floods, coastal flooding, and hurricane-related flooding.

Rank	County	Total Events	River Floods	Flash Floods
1	Polk County	295	177	118
2	Black Hawk County	202	158	44
3	Clay County	188	170	18
4	Clayton County	185	149	36
5	Dallas County	174	121	53
6	Sioux County	163	122	41
7	Webster County	158	102	56
8	Mahaska County	146	117	29
9	Scott County	144	80	64
10	Story County	142	78	64
11	Plymouth County	138	116	22
12	Warren County	138	100	38
13	Marion County	137	100	37
14	Butler County	128	100	28
15	Wapello County	119	82	37
16	Dickinson County	112	81	31
17	Lucas County	107	90	17
18	Lyon County	101	89	12
19	Des Moines County	98	65	33
20	Clinton County	91	55	36
21	Dubuque County	90	22	68
22	Marshall County	90	67	23
23	Kossuth County	90	66	24
24	Lee County	89	54	35
25	Buchanan County	88	28	60
26	Wayne County	88	61	27
27	Humboldt County	86	75	11
28	Fremont County	85	79	6
29	Linn County	85	27	58
30	Emmet County	84	71	13
31	Louisa County	84	57	27
32	Muscatine County	83	52	31
33	Woodbury County	83	44	39
34	Cerro Gordo County	82	50	32
35	Guthrie County	80	39	41
36	Johnson County	74	25	49
37	O'Brien County	73	54	19
38	Fayette County	72	44	28
39	Hamilton County	72	51	21
40	Appanoose County	71	33	38
41	Allamakee County	70	37	33
42	Monroe County	70	36	34
43	Buena Vista County	70	53	17
44	Iowa County	69	32	37
45	Cherokee County	67	42	25
46	Tama County	65	46	19
47	Winneshiek County	65	33	32
48	Wright County	65	41	24
49	Jasper County	65	53	12
50	Boone County	64	38	26
51	Decatur County	63	44	19
52	Floyd County	63	41	22
53	Franklin County	63	37	26
54	Greene County	63	49	14
55	Clarke County	63	42	21
56	Palo Alto County	63	44	19
57	Calhoun County	61	38	23
58	Washington County	61	32	29
59	Carroll County	61	45	16
60	Hardin County	59	38	21
61	Bremer County	58	34	24
62	Grundy County	56	36	20
63	Madison County	55	34	21
64	Sac County	52	33	19
65	Jones County	52	26	26
66	Cass County	51	17	34
67	Pottawattamie County	48	29	19
68	Worth County	48	19	29
69	Jackson County	46	26	20
70	Chickasaw County	44	17	27
71	Benton County	44	19	25
72	Pocahontas County	43	35	8
73	Mitchell County	43	21	22
74	Hancock County	42	37	5
75	Delaware County	42	12	30
76	Adams County	40	14	26
77	Van Buren County	40	17	23
78	Adair County	40	21	19
79	Keokuk County	39	24	15
80	Union County	39	13	26
81	Winnebago County	37	25	12
82	Poweshiek County	36	25	11
83	Taylor County	35	19	16
84	Audubon County	34	23	11
85	Crawford County	34	14	20
86	Howard County	34	14	20
87	Davis County	33	15	18
88	Cedar County	32	15	17
89	Mills County	32	26	6
90	Harrison County	31	20	11
91	Ringgold County	31	11	20
92	Montgomery County	29	21	8
93	Henry County	27	10	17
94	Ida County	24	14	10
95	Jefferson County	23	9	14
96	Monona County	23	12	11
97	Page County	23	18	5
98	Osceola County	12	8	4
99	Shelby County	5	1	4

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

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