15th ST N-Us 87 over Missouri R-Rivers Trail
FairCascade County, Montana · Great FALLS-15th ST N · Structure no. P00010003+05341
- Built
- 1962
- 63 years old, rebuilt 1982
- Condition
- Fair
- inspected August 2023
- Type
- Girder and Floorbeam System
- Steel Continuous
- Length
- 1,126 ft
- 6 main spans
- Daily traffic
- 14,369
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
15th ST N-Us 87 over Missouri R-Rivers Trail is a steel continuous girder and floorbeam system carrying 15th ST N-Us 87 over Missouri R-Rivers Trail in Cascade County, Montana. It was built in 1962 and reconstructed in 1982, so it is 63 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 14,369 vehicles a day, roughly 1% of them trucks, projected to reach 15,087 by 2043. The structure is 1,126 ft (343.1 m) long and 67 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 | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| 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 | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was 15th ST N-Us 87 over Missouri R-Rivers Trail built?
It was built in 1962, making it 63 years old in 2025. It was reconstructed in 1982.
What condition is 15th ST N-Us 87 over Missouri R-Rivers Trail 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 August 2023.
How much traffic does 15th ST N-Us 87 over Missouri R-Rivers Trail carry?
About 14,369 vehicles per day (2023 count), of which roughly 1% are trucks.
How long is 15th ST N-Us 87 over Missouri R-Rivers Trail?
The structure is 1,126 ft (343.1 m) long with a longest span of 185 ft (56.4 m) and a deck 67 ft wide.
Who owns 15th ST N-Us 87 over Missouri R-Rivers Trail?
It is owned by the State Highway Agency.