Ranking

High-hazard dams by county and state

U.S. states and territories had 17,036 high-hazard dam records, the class in which a failure would probably cost lives, with 2,794 rated Poor or Unsatisfactory and 1,632 with no published condition assessment, as of October 30, 2026, according to the National Inventory of Dams.

17,036
Records of high hazard potential: As of October 30, 2026; 2,794
Rated Poor or Unsatisfactory: October 2026; Of the 15,404 high-hazard records with a condition published.; 1,632
No condition published: October 2026; Not provided to the NID, or empty in its file.

Of 17,036 records of high hazard potential, 2,794 are rated Poor or Unsatisfactory, and the NID publishes no condition for 1,632

Records of high hazard potential in the National Inventory of Dams by its condition assessment, as of October 30, 2026. Not published counts the records whose assessment is not provided to the NID or is empty in its file; Not Rated is the NID’s own category.

Each state or federal agency assesses the condition of its own dams, and the share not rated differs from one to another, so a count of records rated Poor or Unsatisfactory is a count of ratings, not a comparison of dams.

Source: The National Inventory of Dams

About this chart

The figures

Of 17,036 records of high hazard potential, 2,794 are rated Poor or Unsatisfactory, and the NID publishes no condition for 1,632. Records of high hazard potential in the National Inventory of Dams by its condition assessment, as of October 30, 2026. Not published counts the records whose assessment is not provided to the NID or is empty in its file; Not Rated is the NID’s own category.
Condition assessment	Records	Share of records with a condition published
Satisfactory	5,301	34.4%
Fair	5,158	33.5%
Poor	2,289	14.9%
Unsatisfactory	505	3.3%
Not Rated	2,151	14.0%
Not published	1,632	not applicable

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<figure style="margin:0;max-width:960px">
  <img src="https://americanfactbook.org/embed/chart/dams-high-hazard-by-condition.svg" alt="Of 17,036 records of high hazard potential, 2,794 are rated Poor or Unsatisfactory, and the NID publishes no condition for 1,632" style="width:100%;height:auto" loading="lazy">
  <figcaption style="font:13px/1.4 system-ui,sans-serif">Chart: <a href="https://americanfactbook.org/dams">Of 17,036 records of high hazard potential, 2,794 are rated Poor or Unsatisfactory, and the NID publishes no condition for 1,632</a>, American Factbook, <a href="https://creativecommons.org/licenses/by/4.0/">CC BY 4.0</a></figcaption>
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The high-hazard records in your state and county

Every state and territory the NID names, October 2026

52 states and territories, most high-hazard records first; each opens its own page, which lists its counties. States rate their own dams, so a column of ratings is not a comparison between states. The ranking, with the map

6 more columns on a wider screen

Records of high hazard potential in the National Inventory of Dams by condition assessment, in 52 states and territories, as of October 30, 2026
Rank	State or territory	High-hazard records	Satisfactory	Fair	Poor	Unsatisfactory	Not Rated	Not published
1	North Carolina	1,677	240	1,007	208	39	90	93
2	Texas	1,648	250	703	105	112	442	36
3	Missouri	1,478	449	0	1	34	978	16
4	California	876	613	99	45	3	6	110
5	Pennsylvania	788	271	326	134	11	5	41
6	South Carolina	679	42	442	145	17	24	9
7	Georgia	556	254	65	189	4	19	25
8	Colorado	474	234	123	0	37	14	66
9	Virginia	452	190	146	59	7	35	15
10	New York	448	247	80	109	5	1	6
11	West Virginia	447	211	43	38	2	103	50
12	Oklahoma	446	31	290	32	8	29	56
13	Ohio	421	101	126	128	4	6	56
14	Washington	409	184	129	46	6	1	43
15	Mississippi	349	83	113	81	59	4	9
16	Massachusetts	342	148	117	42	11	0	24
17	Kansas	328	94	98	74	1	13	48
18	Utah	283	117	98	13	0	0	55
19	Connecticut	282	184	60	16	1	3	18
19	Indiana	282	44	114	89	2	20	13
21	Kentucky	281	22	55	94	17	2	91
22	Tennessee	275	129	14	1	4	0	127
23	New Mexico	255	52	34	136	9	4	20
24	Illinois	252	1	2	0	0	0	249
25	New Jersey	231	132	42	57	0	0	0
26	Alabama	228	20	3	1	1	190	13
27	Montana	215	95	24	32	10	16	38
28	Wisconsin	198	108	77	2	4	3	4
29	Arkansas	194	36	62	21	0	50	25
30	Oregon	173	46	34	18	13	1	61
31	Arizona	170	77	22	27	8	9	27
32	Nebraska	164	100	22	10	0	5	27
33	Nevada	163	6	100	30	13	6	8
33	New Hampshire	163	59	29	60	0	2	13
35	Michigan	161	107	26	15	4	7	2
36	Hawaii	117	0	28	75	12	1	1
37	Maryland	107	35	37	24	9	1	1
38	Idaho	106	23	56	2	2	0	23
39	Florida	104	33	24	3	8	26	10
40	Wyoming	102	5	44	12	2	3	36
41	Iowa	95	64	16	5	0	0	10
41	Rhode Island	95	5	52	34	0	4	0
43	South Dakota	93	10	34	16	7	10	16
44	Maine	79	42	13	9	14	0	1
45	Vermont	69	14	24	19	1	4	7
46	Minnesota	59	24	14	1	0	0	20
47	Delaware	57	5	41	3	0	8	0
48	North Dakota	55	19	10	12	0	5	9
49	Louisiana	42	5	31	2	2	0	2
50	Puerto Rico	36	24	0	10	2	0	0
51	Alaska	31	16	8	4	0	1	2
52	Guam	1	0	1	0	0	0	0

Sources

National Inventory of Dams — national CSV — U.S. Army Corps of Engineers, National Inventory of Dams · U.S. Government work · retrieved November 5, 2026

Compiled automatically from National Inventory of Dams — national CSV by a checked SQL query · Editor: Kian O'Connor · How this site is built

Data retrieved November 5, 2026