Mt 21 over Fort Shaw Canal 110
FairCascade County, Montana · 3M W Simms · Structure no. L07561003+04001
- Built
- 1934
- 91 years old
- Condition
- Fair
- inspected December 2024
- Type
- Tee Beam
- Concrete
- Length
- 39 ft
- 1 main span
- Daily traffic
- 421
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
Mt 21 over Fort Shaw Canal 110 is a concrete tee beam carrying Mt 21 over Fort Shaw Canal 110 in Cascade County, Montana. It was built in 1934, so it is 91 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 421 vehicles a day, roughly 3% of them trucks, projected to reach 442 by 2043. The structure is 39 ft (11.9 m) long and 25 ft wide. If it were closed, the detour would be 60.3 mi (97 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
| 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 Mt 21 over Fort Shaw Canal 110 built?
It was built in 1934, making it 91 years old in 2025.
What condition is Mt 21 over Fort Shaw Canal 110 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 Mt 21 over Fort Shaw Canal 110 carry?
About 421 vehicles per day (2023 count), of which roughly 3% are trucks.
How long is Mt 21 over Fort Shaw Canal 110?
The structure is 39 ft (11.9 m) long with a longest span of 39 ft (11.9 m) and a deck 25 ft wide.
Who owns Mt 21 over Fort Shaw Canal 110?
It is owned by the State Highway Agency.