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 268 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	268	150	118
2	Clay County	183	165	18
3	Black Hawk County	180	136	44
4	Clayton County	179	143	36
5	Sioux County	157	116	41
6	Dallas County	136	83	53
7	Plymouth County	132	110	22
8	Scott County	130	66	64
9	Webster County	124	68	56
10	Warren County	117	79	38
11	Story County	117	53	64
12	Dickinson County	108	77	31
13	Mahaska County	107	78	29
14	Marion County	102	65	37
15	Lyon County	97	85	12
16	Wapello County	97	60	37
17	Butler County	95	67	28
18	Buchanan County	84	24	60
19	Des Moines County	84	51	33
20	Dubuque County	82	14	68
21	Woodbury County	80	41	39
22	Clinton County	79	43	36
23	Lee County	79	44	35
24	Linn County	78	20	58
25	Lucas County	72	55	17
26	Fremont County	70	64	6
27	O'Brien County	70	51	19
28	Fayette County	69	41	28
29	Louisa County	69	42	27
30	Johnson County	66	17	49
31	Allamakee County	65	32	33
32	Muscatine County	65	34	31
33	Buena Vista County	65	48	17
34	Kossuth County	63	39	24
35	Cherokee County	62	37	25
36	Winneshiek County	62	30	32
37	Wayne County	62	35	27
38	Emmet County	60	47	13
39	Humboldt County	59	48	11
40	Cerro Gordo County	59	27	32
41	Iowa County	58	21	37
42	Floyd County	57	35	22
43	Marshall County	57	34	23
44	Appanoose County	57	19	38
45	Washington County	56	27	29
46	Guthrie County	55	14	41
47	Tama County	49	30	19
48	Jones County	47	21	26
49	Palo Alto County	47	28	19
50	Boone County	46	20	26
51	Monroe County	46	12	34
52	Bremer County	45	21	24
53	Cass County	44	10	34
54	Decatur County	44	25	19
55	Chickasaw County	43	16	27
56	Pottawattamie County	43	24	19
57	Hamilton County	42	21	21
58	Wright County	41	17	24
59	Benton County	41	16	25
60	Franklin County	38	12	26
61	Delaware County	38	8	30
62	Keokuk County	37	22	15
63	Madison County	37	16	21
64	Mitchell County	37	15	22
65	Jackson County	36	16	20
66	Van Buren County	36	13	23
67	Jasper County	35	23	12
68	Worth County	35	6	29
69	Grundy County	34	14	20
70	Howard County	33	13	20
71	Adams County	32	6	26
72	Hardin County	31	10	21
73	Union County	31	5	26
74	Clarke County	31	10	21
75	Calhoun County	30	7	23
76	Sac County	30	11	19
77	Crawford County	29	9	20
78	Greene County	27	13	14
79	Adair County	27	8	19
80	Carroll County	27	11	16
81	Harrison County	26	15	11
82	Mills County	26	20	6
83	Taylor County	26	10	16
84	Cedar County	25	8	17
85	Henry County	25	8	17
86	Montgomery County	25	17	8
87	Davis County	23	5	18
88	Ringgold County	23	3	20
89	Ida County	21	11	10
90	Jefferson County	21	7	14
91	Monona County	21	10	11
92	Poweshiek County	21	10	11
93	Page County	20	15	5
94	Audubon County	19	8	11
95	Winnebago County	15	3	12
96	Pocahontas County	14	6	8
97	Hancock County	13	8	5
98	Osceola County	10	6	4
99	Shelby County	4	0	4

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

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