Montana Dams
2,990 dams tracked by the National Inventory of Dams
Total Dams
2,990
High Hazard
188
6.3%
Poor / Unsatisfactory
132
Average Age
74 yrs
Hazard Classification
High188 (6.3%)
Significant193 (6.5%)
Low2,606 (87.2%)
Condition Assessment
Satisfactory113 (3.8%)
Fair44 (1.5%)
Poor / Unsatisfactory132 (4.4%)
Not Rated2,701 (90.3%)
Federal
278
State
151
Local
84
Private
2,466
Tallest Dams
- Yankee Doodle Tailings Dam570 ft
- Hungry Horse Dam564 ft
- Libby Dam422 ft
- Noxon Rapids260 ft
- Fort Peck Dam256 ft
High Hazard Dams
- Yankee Doodle Tailings DamHigh
- Hungry Horse DamHigh
- Libby DamHigh
- Noxon RapidsHigh
- Fort Peck DamHigh
Poor Condition Dams
All Dams in Montana
Showing 2001–2025 of 2,990
| Dam Name | Height (ft) | Year | Hazard | Condition |
|---|---|---|---|---|
| No. Decker Flood Control Reservoir No. 2 Big Horn County | 52 | — | Significant | Fair |
| Noel #1 Phillips County | 12 | 1945 | Low | Not Rated |
| Noel #2 Phillips County | 10 | 1925 | Low | Not Rated |
| Noel #3 Phillips County | 20 | 1945 | Low | Not Rated |
| Nollmeyer #1 Park County | 25 | 1975 | Low | Not Rated |
| Nomland Dam McCone County | 16 | 1964 | Low | Not Rated |
| None Phillips County | 20 | 1949 | Low | Not Rated |
| Norman #2 Fergus County | 27 | 1999 | Low | Not Rated |
| Norman #4 (Fergus) Fergus County | 21 | 1945 | Low | Not Rated |
| North Beaver Detention Dam Valley County | 19 | 1957 | Low | Unsatisfactory |
| Northern Pacific Reservoir Dam Jefferson County | 35 | 1935 | High | Not Rated |
| North Fork of Smith River Dam Meagher County | 91 | 1936 | High | Satisfactory |
| North Fork Plug Dam Valley County | 19 | — | Low | Unsatisfactory |
| North Fork Red Lodge Reservoir Carbon County | 18 | 1920 | Low | Not Rated |
| North Place Dam McCone County | 20 | 1955 | Low | Not Rated |
| North Roy Fergus County | 27 | 1964 | Low | Not Rated |
| North Tucks Slough Dam Beaverhead County | 13 | 1990 | Low | Poor |
| Norwegian Creek Dam Madison County | 85 | 1958 | Significant | Not Rated |
| Noxon Rapids Sanders County | 260 | 1960 | High | Fair |
| Nuhn #2 Carter County | 18 | 1949 | Low | Not Rated |
| Nuhn #3 Carter County | 35 | 1965 | Low | Not Rated |
| Number Twenty Reservoir Phillips County | 10 | 1950 | Low | Not Rated |
| Nyquist #1 Valley County | 15 | 1960 | Low | Not Rated |
| Oak Blaine County | 25 | 1935 | Low | Not Rated |
| Oak Ridge Teton County | 15 | 1943 | Low | Not Rated |
Data sourced from the National Inventory of Dams (NID). Hazard classification reflects potential consequences of failure, not the likelihood of failure.