I 15 over Big Sheep Creek
FairBeaverhead County, Montana · 0.6M S Dell · Structure no. I00015023+02102
- Built
- 1971
- 54 years old
- Condition
- Fair
- inspected July 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 37 ft
- 1 main span
- Daily traffic
- 1,863
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I 15 over Big Sheep Creek is a prestressed concrete stringer/multi-beam or girder carrying I 15 over Big Sheep Creek in Beaverhead County, Montana. It was built in 1971, 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 1,863 vehicles a day, roughly 29% of them trucks, projected to reach 1,993 by 2043. The structure is 37 ft (11.3 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 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 | 7 Good | Some minor problems. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 8 Very Good | No problems noted. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I 15 over Big Sheep Creek built?
It was built in 1971, making it 54 years old in 2025.
What condition is I 15 over Big Sheep Creek 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 July 2024.
How much traffic does I 15 over Big Sheep Creek carry?
About 1,863 vehicles per day (2023 count), of which roughly 29% are trucks.
How long is I 15 over Big Sheep Creek?
The structure is 37 ft (11.3 m) long with a longest span of 35 ft (10.7 m) and a deck 44 ft wide.
Who owns I 15 over Big Sheep Creek?
It is owned by the State Highway Agency.