IRR - S 73 over Little Bighorn River
FairBig Horn County, Montana · Lodge Grass · Structure no. S00463000+03221
- Built
- 1980
- 45 years old
- Condition
- Fair
- inspected December 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 103 ft
- 1 main span
- Daily traffic
- 548
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
IRR - S 73 over Little Bighorn River is a prestressed concrete stringer/multi-beam or girder carrying IRR - S 73 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 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 548 vehicles a day, roughly 2% of them trucks, projected to reach 575 by 2043. The structure is 103 ft (31.4 m) long and 46 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 | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| 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 73 over Little Bighorn River built?
It was built in 1980, making it 45 years old in 2025.
What condition is IRR - S 73 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 December 2024.
How much traffic does IRR - S 73 over Little Bighorn River carry?
About 548 vehicles per day (2023 count), of which roughly 2% are trucks.
How long is IRR - S 73 over Little Bighorn River?
The structure is 103 ft (31.4 m) long with a longest span of 100 ft (30.5 m) and a deck 46 ft wide.
Who owns IRR - S 73 over Little Bighorn River?
It is owned by the State Highway Agency.