Koocanusa Bridge over Koocanusa Reservoir
FairLincoln County, Montana · Lake Koocanusa · Structure no. 011401000000046
- Built
- 1971
- 54 years old, rebuilt 1983
- Condition
- Fair
- inspected April 2023
- Type
- Truss - Deck
- Steel
- Length
- 2,437 ft
- 6 main spans
- Daily traffic
- 75
- 1990 count
- Owner
- Federal
- U.S. Forest Service
About this bridge
Koocanusa Bridge over Koocanusa Reservoir is a steel truss - deck carrying Koocanusa Bridge over Koocanusa Reservoir in Lincoln County, Montana. It was built in 1971 and reconstructed in 1983, so it is 54 years old, older than the Montana average of 47 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 75 vehicles a day, projected to reach 112 by 2045. The structure is 2,437 ft (742.8 m) long and 33 ft wide. If it were closed, the detour would be 84.5 mi (136 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Koocanusa Bridge over Koocanusa Reservoir built?
It was built in 1971, making it 54 years old in 2025. It was reconstructed in 1983.
What condition is Koocanusa Bridge over Koocanusa Reservoir in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in April 2023.
How much traffic does Koocanusa Bridge over Koocanusa Reservoir carry?
About 75 vehicles per day (1990 count).
How long is Koocanusa Bridge over Koocanusa Reservoir?
The structure is 2,437 ft (742.8 m) long with a longest span of 2,382 ft (726 m) and a deck 33 ft wide.
Who owns Koocanusa Bridge over Koocanusa Reservoir?
It is owned by the U.S. Forest Service.