Libby Dam
Libby Dam is a gravity dam located in Lincoln County, Montana, built in 1973. It carries a High hazard potential classification.
About Libby Dam
The primary purpose of Libby Dam 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 Usace - Seattle District (federal). It impounds the Kootenai River near Libby.
The dam stands 422 feet tall and stretches 2,890 feet across, creates a reservoir covering 46,500 acres, has a maximum storage capacity of 6,027,000 acre-feet, and collects water from a drainage area of 8,985 square miles. Completed in 1973, the structure is well into its service life at over 50 years 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. An emergency action plan is in place for this dam. The most recent inspection on record was 07/16/2025.
At 422 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 | Lincoln |
| Nearest City | Libby |
| River/Stream | Kootenai River |
| Coordinates | 48.41029, -115.31427 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 422 ft |
| Dam Length | 2,890 ft |
| Year Completed | 1973 (53 years old) |
Storage & Hydraulics
| NID Storage | 6,027,000 acre-ft |
| Max Storage | 6,027,000 acre-ft |
| Normal Storage | 5,809,000 acre-ft |
| Surface Area | 46,500 acres |
| Drainage Area | 8,985 sq mi |
| Max Discharge | 150,000 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | USACE - Seattle District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 07/16/2025 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MT00652 |
| Federal ID | MT00652 |
| More Info | State Dam Safety Program |