IRR - S 451 over Little Bighorn River
FairBig Horn County, Montana · 4M N Wyola · Structure no. S00451024+09811
- Built
- 1950
- 75 years old
- Condition
- Fair
- inspected October 2024
- Type
- Stringer/Multi-beam or Girder
- Steel Continuous
- Length
- 120 ft
- 2 main spans
- Daily traffic
- 382
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
IRR - S 451 over Little Bighorn River is a steel continuous stringer/multi-beam or girder carrying IRR - S 451 over Little Bighorn River in Big Horn County, Montana. It was built in 1950, so it is 75 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 382 vehicles a day, roughly 3% of them trucks, projected to reach 401 by 2043. The structure is 120 ft (36.6 m) long and 35 ft wide. If it were closed, the detour would be 123.7 mi (199 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was IRR - S 451 over Little Bighorn River built?
It was built in 1950, making it 75 years old in 2025.
What condition is IRR - S 451 over Little Bighorn 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 October 2024.
How much traffic does IRR - S 451 over Little Bighorn River carry?
About 382 vehicles per day (2023 count), of which roughly 3% are trucks.
How long is IRR - S 451 over Little Bighorn River?
The structure is 120 ft (36.6 m) long with a longest span of 60 ft (18.3 m) and a deck 35 ft wide.
Who owns IRR - S 451 over Little Bighorn River?
It is owned by the State Highway Agency.