Route 108 over Sun River
FairTeton County, Montana · Sun River · Structure no. 011501000000009
- Built
- 1967
- 58 years old, rebuilt 1995
- Condition
- Fair
- inspected May 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 215 ft
- 3 main spans
- Daily traffic
- 113
- 1991 count
- Owner
- Federal
- U.S. Forest Service
About this bridge
Route 108 over Sun River is a prestressed concrete stringer/multi-beam or girder carrying Route 108 over Sun River in Teton County, Montana. It was built in 1967 and reconstructed in 1995, so it is 58 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 5 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 113 vehicles a day, roughly 5% of them trucks, projected to reach 169 by 2045. The structure is 215 ft (65.5 m) long and 29 ft wide. If it were closed, the detour would be 98.2 mi (158 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 | 7 Good | Some minor problems. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Channel and channel protection | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Route 108 over Sun River built?
It was built in 1967, making it 58 years old in 2025. It was reconstructed in 1995.
What condition is Route 108 over Sun River 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 May 2023.
How much traffic does Route 108 over Sun River carry?
About 113 vehicles per day (1991 count), of which roughly 5% are trucks.
How long is Route 108 over Sun River?
The structure is 215 ft (65.5 m) long with a longest span of 70 ft (21.3 m) and a deck 29 ft wide.
Who owns Route 108 over Sun River?
It is owned by the U.S. Forest Service.