High Hazard Dams
Loss of human life is likely if the dam fails.
| Dam Name | Hazard | Height | Built | Type | State |
|---|---|---|---|---|---|
| Arcadia Dam Oklahoma | High Hazard | 102 ft | 1986 | Earth | Oklahoma |
| Arcadia Woods Lake Dam Richland | High Hazard | 22 ft | 1937 | — | South Carolina |
| Archbold Upground Reservoir No. 1 Fulton | High Hazard | 15 ft | 1957 | Earth | Ohio |
| Archbold Upground Reservoir No. 2 Fulton | High Hazard | 22 ft | 1961 | Earth | Ohio |
| Archer City Lake Dam Archer | High Hazard | 24 ft | 1911 | Earth | Texas |
| Arclar/Willow Lake/Refuse Area 2 Dam Saline | High Hazard | 108 ft | — | Earth | Illinois |
| Arc Redevelopment Swm Pond Dam Prince William | High Hazard | 22 ft | — | Earth | Virginia |
| Arctic Kent | High Hazard | 28 ft | 1885 | Masonry | Rhode Island |
| Ardrey Park Dam Mecklenburg | High Hazard | — | — | Earth | North Carolina |
| Arentsen Pond Dam Hamilton | High Hazard | 75 ft | 1992 | Earth | Illinois |
| Argo Dam Washtenaw | High Hazard | 18 ft | 1920 | Gravity | Michigan |
| Argo Reservoir Dam Prairie | High Hazard | 19 ft | 1954 | Earth | Arkansas |
| Argyle Lake Dam Osage | High Hazard | 25 ft | 1904 | Earth | Missouri |
| Argyle No. 2 Contra Costa | High Hazard | 27 ft | 1970 | Other | California |
| Arjay Slurry Impoundment Bell | High Hazard | 355 ft | — | Earth | Kentucky |
| Arkabutla Dam DeSoto | High Hazard | 65 ft | 1943 | Earth | Mississippi |
| Arkport Dam Steuben | High Hazard | 131 ft | 1940 | Earth | New York |
| Arlington Mills Res Wheeler Dam Rockingham | High Hazard | 54 ft | 1922 | Concrete | New Hampshire |
| Arlington Reservoir Dam Middlesex | High Hazard | 14 ft | 1872 | Earth | Massachusetts |
| Arlington Southwest Nature Preserve Dam Tarrant | High Hazard | 24 ft | 1989 | Earth | Texas |
| Arm Brook Pl-566 Flood Control Dam Hampden | High Hazard | 58 ft | 1963 | Earth | Massachusetts |
| Armstrong Lake Dam Bandera | High Hazard | 26 ft | 1964 | Earth | Texas |
| Armstrong Park Flood Control Reservoir Dam DuPage | High Hazard | 22 ft | — | Earth | Illinois |
| Armstrong Pond Dam Norfolk | High Hazard | 20 ft | — | Concrete | Massachusetts |
| Army Residence Community Dam Bexar | High Hazard | 14 ft | — | Earth | Texas |
| Arnault Branch Mine Dam Washington | High Hazard | 46 ft | 1970 | Other | Missouri |
| Arnett Lake Dam Pike | High Hazard | 22 ft | 1973 | Earth | Ohio |
| Arnold Palmer Dam Mecklenburg | High Hazard | — | 1987 | Earth | North Carolina |
| Arnold Pond Kent | High Hazard | 13 ft | 1940 | Gravity | Rhode Island |
| Arnolds Lake Dam Greene | High Hazard | 15 ft | 1965 | Earth | Arkansas |
| Arnoname 186 Ozark Interests Montgomery | High Hazard | 16 ft | 1962 | Earth | Arkansas |
| Arnoname 55 Union | High Hazard | 10 ft | 1924 | Earth | Arkansas |
| Arrington Lake Dam Madison | High Hazard | 12 ft | — | Earth | Mississippi |
| Arrow Canyon Detention Dam Clark | High Hazard | — | 1933 | — | Nevada |
| Arrowhead Estates-Lower-Dam(Shallow) St. Louis | High Hazard | 30 ft | 1955 | Earth | Missouri |
| Arrowhead Estates-Upper-Dam(Shallow) St. Louis | High Hazard | 30 ft | 1955 | Earth | Missouri |
| Arrowhead Lake Monroe | High Hazard | 18 ft | 1954 | Earth | Pennsylvania |
| Arrowhead Lake Dam Union | High Hazard | 22 ft | 1947 | Earth | Mississippi |
| Arrowhead Lake Dam Boone | High Hazard | 38 ft | 1995 | Earth | Missouri |
| Arrowhead Lake Dam Spartanburg | High Hazard | 28 ft | — | — | South Carolina |
| Arrowhead Lake Dam Transylvania | High Hazard | — | 1952 | Earth | North Carolina |
| Arrowhead Lake Dam Transylvania | High Hazard | — | — | Earth | North Carolina |
| Arrowhead Lakes Lower Dam Dent | High Hazard | 27 ft | 1973 | Earth | Missouri |
| Arrow Lake Maury | High Hazard | — | 1921 | Earth | Tennessee |
| Arrowood Lake Dam Gaston | High Hazard | — | 1955 | Earth | North Carolina |
| Arrowood Quarry Dam Mecklenburg | High Hazard | — | 1968 | Earth | North Carolina |
| Arrowrock Boise | High Hazard | 350 ft | 1915 | Concrete | Idaho |
| Arrow Wood Lake Dam Madison | High Hazard | 15 ft | 2000 | — | Illinois |
| Arroyo Del Oso Detention Dam Bernalillo | High Hazard | 38 ft | 1956 | Earth | New Mexico |
| Arroyo Seco Amador | High Hazard | 67 ft | 1957 | Earth | California |