I 15 over Boulder River
GoodJefferson County, Montana · 4.3M S Basin · Structure no. I00015151+09402
- Built
- 1985
- 40 years old
- Condition
- Good
- inspected April 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 98 ft
- 1 main span
- Daily traffic
- 1,591
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I 15 over Boulder River is a prestressed concrete stringer/multi-beam or girder carrying I 15 over Boulder River in Jefferson County, Montana. It was built in 1985, so it is 40 years old, younger than the Montana average of 47 years.
The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
It carries about 1,591 vehicles a day, roughly 16% of them trucks, projected to reach 1,718 by 2043. The structure is 98 ft (29.9 m) long and 47 ft wide. If it were closed, the detour would be 1.2 mi (2 km).
Location
Open in Google MapsCondition and inspection
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 7 Good | Some minor problems. |
| 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 Boulder River built?
It was built in 1985, making it 40 years old in 2025.
What condition is I 15 over Boulder River in?
The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in April 2024.
How much traffic does I 15 over Boulder River carry?
About 1,591 vehicles per day (2023 count), of which roughly 16% are trucks.
How long is I 15 over Boulder River?
The structure is 98 ft (29.9 m) long with a longest span of 95 ft (29 m) and a deck 47 ft wide.
Who owns I 15 over Boulder River?
It is owned by the State Highway Agency.