Most Flood-Prone Counties in Pennsylvania

Based on NOAA Storm Events Database records from 1996 to 2025, these are the Pennsylvania counties with the most recorded flood events. Allegheny County tops the list with 595 events. The data includes river floods, flash floods, coastal flooding, and hurricane-related flooding.

Rank	County	Total Events	River Floods	Flash Floods
1	Allegheny County	595	99	496
2	Westmoreland County	322	84	238
3	Chester County	293	70	223
4	Montgomery County	263	71	192
5	Berks County	223	46	177
6	Philadelphia County	220	77	143
7	Delaware County	196	52	144
8	Washington County	195	52	143
9	Bucks County	175	53	122
10	Bradford County	174	15	159
11	Fayette County	157	38	119
12	Beaver County	146	51	95
13	Lancaster County	135	29	106
14	Luzerne County	129	18	111
15	Northampton County	127	28	99
16	York County	120	24	96
17	Lawrence County	119	25	94
18	Lehigh County	116	21	95
19	Jefferson County	105	51	54
20	Butler County	103	28	75
21	Mercer County	100	18	82
22	Susquehanna County	99	2	97
23	Lackawanna County	93	9	84
24	Venango County	93	22	71
25	Greene County	85	30	55
26	Indiana County	80	24	56
27	Somerset County	78	17	61
28	Monroe County	76	13	63
29	Armstrong County	70	19	51
30	Erie County	68	6	60
31	Crawford County	67	4	63
32	Clarion County	61	12	49
33	Wayne County	61	4	57
34	Dauphin County	58	16	42
35	Lebanon County	58	15	43
36	Cumberland County	57	19	38
37	Lycoming County	55	17	38
38	Franklin County	54	10	44
39	Wyoming County	54	12	42
40	Carbon County	51	10	41
41	Schuylkill County	49	12	37
42	Bedford County	48	9	39
43	Blair County	47	10	37
44	Adams County	44	14	30
45	Clearfield County	44	7	37
46	Huntingdon County	43	13	30
47	Cambria County	41	6	35
48	Columbia County	39	9	30
49	Tioga County	39	12	27
50	Northumberland County	35	8	27
51	Sullivan County	34	11	23
52	Union County	32	12	20
53	Centre County	31	9	22
54	McKean County	31	5	26
55	Perry County	30	12	18
56	Warren County	30	3	27
57	Potter County	25	7	18
58	Fulton County	24	9	15
59	Snyder County	24	7	17
60	Juniata County	19	4	15
61	Pike County	19	2	17
62	Clinton County	17	6	11
63	Montour County	16	4	12
64	Forest County	15	3	12
65	Mifflin County	12	4	8
66	Elk County	9	2	7
67	Cameron County	7	2	5

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

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Most Flood-Prone Counties in Pennsylvania

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