IRR - S 451 over Little Bighorn River
GoodBig Horn County, Montana · 3M S Garryowen Int · Structure no. S00451002+07801
- Built
- 1980
- 45 years old
- Condition
- Good
- inspected July 2023
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 161 ft
- 2 main spans
- Daily traffic
- 915
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
IRR - S 451 over Little Bighorn River is a prestressed concrete stringer/multi-beam or girder carrying IRR - S 451 over Little Bighorn River in Big Horn County, Montana. It was built in 1980, so it is 45 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 915 vehicles a day, roughly 2% of them trucks, projected to reach 961 by 2043. The structure is 161 ft (49.2 m) long and 34 ft wide. If it were closed, the detour would be 31.7 mi (51 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 | 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 1980, making it 45 years old in 2025.
What condition is IRR - S 451 over Little Bighorn 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 July 2023.
How much traffic does IRR - S 451 over Little Bighorn River carry?
About 915 vehicles per day (2023 count), of which roughly 2% are trucks.
How long is IRR - S 451 over Little Bighorn River?
The structure is 161 ft (49.2 m) long with a longest span of 81 ft (24.7 m) and a deck 34 ft wide.
Who owns IRR - S 451 over Little Bighorn River?
It is owned by the State Highway Agency.