I 15 over Marias River
GoodToole County, Montana · 6M S Shelby · Structure no. I00015357+00752
- Built
- 1976
- 49 years old
- Condition
- Good
- inspected August 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 484 ft
- 5 main spans
- Daily traffic
- 1,311
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I 15 over Marias River is a prestressed concrete stringer/multi-beam or girder carrying I 15 over Marias River in Toole County, Montana. It was built in 1976, so it is 49 years old, older 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 1,311 vehicles a day, roughly 34% of them trucks, projected to reach 1,376 by 2043. The structure is 484 ft (147.5 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
All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 8 Very Good | No problems noted. |
| Superstructure | 8 Very Good | No problems noted. |
| Substructure | 7 Good | Some minor problems. |
| Channel and channel protection | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I 15 over Marias River built?
It was built in 1976, making it 49 years old in 2025.
What condition is I 15 over Marias 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 August 2023.
How much traffic does I 15 over Marias River carry?
About 1,311 vehicles per day (2023 count), of which roughly 34% are trucks.
How long is I 15 over Marias River?
The structure is 484 ft (147.5 m) long with a longest span of 127 ft (38.6 m) and a deck 44 ft wide.
Who owns I 15 over Marias River?
It is owned by the State Highway Agency.