Black Eagle
Black Eagle is a gravity dam located in Cascade County, Montana, built in 1891. It carries a High hazard potential classification and has a poor condition assessment.
About Black Eagle
The primary purpose of Black Eagle is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Northwestern Energy (private). It impounds the Missouri River near Fort Benton.
The dam stands 41 feet tall and stretches 1,670 feet across, creates a reservoir covering 402 acres, has a storage capacity of 1,710 acre-feet, and collects water from a drainage area of 22,100 square miles. Completed in 1891, the structure is over a century old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 07/19/2022.
At 41 feet, this dam is taller than 88% of dams nationwide.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Montana dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Montana |
| County | Cascade |
| Nearest City | Fort Benton |
| River/Stream | Missouri River |
| Coordinates | 47.51970, -111.26310 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 41 ft |
| Dam Height | 35 ft |
| Dam Length | 1,670 ft |
| Year Completed | 1891 (135 years old) |
Storage & Hydraulics
| NID Storage | 1,710 acre-ft |
| Normal Storage | 1,710 acre-ft |
| Surface Area | 402 acres |
| Drainage Area | 22,100 sq mi |
| Max Discharge | 94,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | NorthWestern Energy |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 07/19/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MT00558 |
| Federal ID | MT00558 |
| More Info | State Dam Safety Program |