Fort Peck Dam
Fort Peck Dam is an earth dam located in McCone County, Montana, built in 1940. It carries a High hazard potential classification.
About Fort Peck Dam
The primary purpose of Fort Peck Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Usace - Omaha District (federal). It impounds the Missouri River near Nashua.
The dam stands 256 feet tall and stretches 21,026 feet across, creates a reservoir covering 93,000 acres, has a maximum storage capacity of 19,100,000 acre-feet, and collects water from a drainage area of 57,725 square miles. Completed in 1940, the structure is well-established, with more than 75 years of service.
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. An emergency action plan is in place for this dam. The most recent inspection on record was 09/20/2024.
At 256 feet, this dam is taller than 99% of all dams in the United States.
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 | McCone |
| Nearest City | Nashua |
| River/Stream | Missouri River |
| Coordinates | 48.00223, -106.41799 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 256 ft |
| Dam Length | 21,026 ft |
| Year Completed | 1940 (86 years old) |
Storage & Hydraulics
| NID Storage | 19,100,000 acre-ft |
| Max Storage | 19,100,000 acre-ft |
| Normal Storage | 15,400,000 acre-ft |
| Surface Area | 93,000 acres |
| Drainage Area | 57,725 sq mi |
| Max Discharge | 250,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - Omaha District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 09/20/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MT00025 |
| Federal ID | MT00025 |
| More Info | State Dam Safety Program |