Old US HWY 91 over Muddy Creek Slough 111
FairPosted for loadCascade County, Montana · Ulm · Structure no. L07603000+09001
- Built
- 1923
- 102 years old
- Condition
- Fair
- inspected January 2025
- Type
- Stringer/Multi-beam or Girder
- Steel
- Length
- 34 ft
- 1 main span
- Daily traffic
- 100
- 2025 count
- Owner
- State
- State Highway Agency
About this bridge
Old US HWY 91 over Muddy Creek Slough 111 is a steel stringer/multi-beam or girder carrying Old US HWY 91 over Muddy Creek Slough 111 in Cascade County, Montana. It was built in 1923, so it is 102 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. Its operating status is: posted for load restriction.
It carries about 100 vehicles a day, roughly 3% of them trucks, projected to reach 100 by 2040. The structure is 34 ft (10.4 m) long and 21 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 | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 7 Good | Some minor problems. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Old US HWY 91 over Muddy Creek Slough 111 built?
It was built in 1923, making it 102 years old in 2025.
What condition is Old US HWY 91 over Muddy Creek Slough 111 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 January 2025.
How much traffic does Old US HWY 91 over Muddy Creek Slough 111 carry?
About 100 vehicles per day (2025 count), of which roughly 3% are trucks.
How long is Old US HWY 91 over Muddy Creek Slough 111?
The structure is 34 ft (10.4 m) long with a longest span of 33 ft (10.1 m) and a deck 21 ft wide.
Who owns Old US HWY 91 over Muddy Creek Slough 111?
It is owned by the State Highway Agency.