Dams: records in the National Inventory of Dams, by hazard class and condition
The National Inventory of Dams holds 92,692 records as of October 30, 2026, and 17,036 of them carry the high hazard class. The NID defines it: “Dams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.” A record is one entry in the inventory, and it includes the separate structures recorded with a dam, so a count is of records.
The inventory, October 2026
- 17,036 18.4% of records
- High-hazard records
- October 2026
- Of 92,692 records in the NID. A hazard class is not a risk.
- 92,692
- Records in the inventory
- October 2026
- Each entry in the NID, separate structures recorded with a dam included.
- 15,404
- High hazard, condition published
- October 2026
- 2,794 rated Poor or Unsatisfactory; the NID publishes no condition for 1,632.
- 2,472
- High hazard, no required emergency action plan
- October 2026
- The NID’s answer No, for a plan that is required and not prepared; of 17,036 high-hazard records.
About these figures
- High-hazard records
- Of 92,692 records in the NID. A hazard class is not a risk.
- Records in the inventory
- Each entry in the NID, separate structures recorded with a dam included.
- High hazard, condition published
- 2,794 rated Poor or Unsatisfactory; the NID publishes no condition for 1,632.
- High hazard, no required emergency action plan
- The NID’s answer No, for a plan that is required and not prepared; of 17,036 high-hazard records.
What stands out
Seven findings. From the National Inventory of Dams, each one a row from a query.
17,036 high-hazard records of the 92,692 records in the National Inventory of Dams carry the high hazard class, 18.4% of the file. The class is the consequence if a dam failed, as the responsible agency assigned it, and not the likelihood of a failure. United States →
North Carolina has the most high-hazard records: 1,677, of the 17,036 high-hazard records across 52 states and territories the NID names. North Carolina →
Of the 17,036 high-hazard records, the NID publishes a condition assessment for 15,404, 2,794 of them rated Poor or Unsatisfactory; for 1,632 it publishes none. United States →
The NID lists 2,472 of the 17,036 high-hazard records as No for an emergency action plan, its answer for a plan that is required and not prepared. United States →
North Carolina has the most high-hazard records answered No for an emergency action plan: 634. North Carolina →
By the NID’s primary owner type, Private has the most high-hazard records: 7,543, of 17,036. Private →
By the NID’s primary purpose, Recreation has the most high-hazard records: 5,803, of 17,036. Recreation →
What changed in this release
This is the hub’s first release, retrieved on November 5, 2026: 17,036 high-hazard records in the National Inventory of Dams at October 30, 2026.
Hazard class by condition
Each hazard class with the condition the NID publishes for its records. A condition the NID does not publish is its own column, never counted under a rating, and Not Rated is the NID’s category for a record not inspected or not rated.
6 more columns on a wider screen
| Hazard class | Records |
|---|---|
| High | 17,036 |
| Significant | 11,350 |
| Low | 60,242 |
| Undetermined | 4,064 |
Records by owner type
| Owner type | Records | High hazard |
|---|---|---|
| Private | 60,388 | 7,543 |
| Local Government | 18,647 | 5,421 |
| State | 6,746 | 1,595 |
| Federal | 3,547 | 1,346 |
| Public Utility | 1,670 | 910 |
| Not Listed | 1,664 | 211 |
| Tribal Government | 18 | 0 |
| Not published | 12 | 10 |
Records by primary purpose
| Primary purpose | Records | High hazard |
|---|---|---|
| Recreation | 30,935 | 5,803 |
| Flood Risk Reduction | 15,183 | 4,253 |
| Fire Protection, Stock, or Small Fish Pond | 11,992 | 275 |
| Irrigation | 7,686 | 1,336 |
| Other | 7,455 | 948 |
| Not published | 5,867 | 637 |
| Water Supply | 5,199 | 2,173 |
| Fish and Wildlife Pond | 3,181 | 209 |
| Hydroelectric | 2,113 | 934 |
| Tailings | 1,206 | 290 |
| Grade Stabilization | 964 | 18 |
| Debris Control | 678 | 100 |
| Navigation | 233 | 60 |
Emergency action plans for high-hazard records
1 more column on a wider screen
| Answer | High-hazard records |
|---|---|
| Yes | 13,191 |
| No | 2,472 |
| Not Required | 1,361 |
| Not published | 12 |
High-hazard records by state
All 52 states and territories, ranked, with the map
The high-hazard records in every state by condition, and your state’s
Everything in this hub
Every page in this topic, by kind.
Questions6
One question per page, answered in the first sentence with the figure.
Rankings2
Each list ordered by one measure, with the figure behind every entry.
Dam records92,692
Each record in the National Inventory of Dams, by its Federal ID: its hazard class and condition under the NID’s definitions, every public field, and the records that share its NID ID. Listed by county.
Compares51
States52
One page per state and the District of Columbia.
Counties3,081
Each county the National Inventory of Dams names: its records by hazard class, the condition of its high-hazard records, and every record there. Listed by state.
More pages1
Single pages of this hub that are not one of a kind.
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
How to cite this page
Cite the page’s address and the date printed on it, and name U.S. Army Corps of Engineers, National Inventory of Dams as the source of the figures.
American Factbook. “Dams.” Updated November 5, 2026. https://americanfactbook.org/dams. Source: National Inventory of Dams — national CSV, https://nid.sec.usace.army.mil/.
Data retrieved