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 2651–2675 of 2,990
| Dam Name | Height (ft) | Year | Hazard | Condition |
|---|---|---|---|---|
| Thebes Lake Rosebud County | 16 | 1913 | Low | Not Rated |
| Thee End Blaine County | 30 | 1964 | Low | Not Rated |
| Thelma #1 Park County | 19 | 1962 | Low | Not Rated |
| The Man Dam Valley County | 22 | — | Low | Not Rated |
| The Moonspinner Toole County | 25 | 1960 | Low | Not Rated |
| The Ox Richland County | 20 | 1960 | Low | Not Rated |
| The Pewter Toole County | 18 | 1925 | Low | Not Rated |
| The Pinta Carter County | 14 | 1977 | Low | Not Rated |
| Thibadeau Farm Hill County | 30 | 1937 | Low | Not Rated |
| Thielen #1 Fallon County | 10 | 1962 | Low | Not Rated |
| Thiellis Carbon County | 18 | 1972 | Low | Not Rated |
| Third Stooges Meagher County | 20 | 1947 | Low | Not Rated |
| Thirtymile Reservoir Blaine County | 14 | 1933 | Low | Not Rated |
| Thomas Sheridan County | 12 | 1939 | Low | Not Rated |
| Thompson Creek Dam(Proposed) Carter County | 15 | — | Low | Not Rated |
| Thompson Falls - Intake Dam B Sanders County | 142 | 1996 | Low | Satisfactory |
| Thompson, Frank Lewis and Clark County | 20 | 1972 | Low | Not Rated |
| Thora #2 McCone County | 17 | 1946 | Low | Not Rated |
| Thorn McCone County | 10 | 1971 | Low | Not Rated |
| Thornton Lake Dam Deer Lodge County | 11 | 1904 | Significant | Not Rated |
| Three Dollar Bill Toole County | 24 | 1970 | Low | Not Rated |
| Three Forks Rosebud County | 17 | 1953 | Low | Not Rated |
| Three Mile Reservoir (L.&C.) Lewis and Clark County | 70 | 1926 | High | Poor |
| Threemile Storage Blaine County | 12 | 1937 | Low | Not Rated |
| Three Pronged Fork Dam Chouteau County | 10 | 1965 | Low | Not Rated |
Data sourced from the National Inventory of Dams (NID). Hazard classification reflects potential consequences of failure, not the likelihood of failure.