IRR BIA RTE 91 over Big Horn River
FairBig Horn County, Montana · 2.4 KM West of St. Xavier · Structure no. 00000000000C208
- Built
- 1970
- 55 years old
- Condition
- Fair
- inspected June 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 525 ft
- 5 main spans
- Daily traffic
- 360
- 2024 count
- Owner
- Federal
- Bureau of Indian Affairs
About this bridge
IRR BIA RTE 91 over Big Horn River is a prestressed concrete stringer/multi-beam or girder carrying IRR BIA RTE 91 over Big Horn River in Big Horn County, Montana. It was built in 1970, so it is 55 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 360 vehicles a day, roughly 20% of them trucks, projected to reach 410 by 2044. The structure is 525 ft (160 m) long and 34 ft wide. If it were closed, the detour would be 34.2 mi (55 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 7 Good | Some minor problems. |
| 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 IRR BIA RTE 91 over Big Horn River built?
It was built in 1970, making it 55 years old in 2025.
What condition is IRR BIA RTE 91 over Big Horn 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 June 2024.
How much traffic does IRR BIA RTE 91 over Big Horn River carry?
About 360 vehicles per day (2024 count), of which roughly 20% are trucks.
How long is IRR BIA RTE 91 over Big Horn River?
The structure is 525 ft (160 m) long with a longest span of 105 ft (32 m) and a deck 34 ft wide.
Who owns IRR BIA RTE 91 over Big Horn River?
It is owned by the Bureau of Indian Affairs.