I 90 over Clark Fork River
PoorMissoula County, Montana · 6.2M E Alberton · Structure no. I00090081+08401
- Built
- 1964
- 61 years old
- Condition
- Poor
- inspected March 2024
- Type
- Girder and Floorbeam System
- Steel Continuous
- Length
- 982 ft
- 4 main spans
- Daily traffic
- 9,168
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
I 90 over Clark Fork River is a steel continuous girder and floorbeam system carrying I 90 over Clark Fork River in Missoula County, Montana. It was built in 1964, so it is 61 years old, older than the Montana average of 47 years.
The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
It carries about 9,168 vehicles a day, roughly 20% of them trucks, projected to reach 9,626 by 2043. The structure is 982 ft (299.2 m) long and 64 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 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 4 Poor | Advanced section loss, deterioration, 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was I 90 over Clark Fork River built?
It was built in 1964, making it 61 years old in 2025.
What condition is I 90 over Clark Fork River in?
The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in March 2024.
How much traffic does I 90 over Clark Fork River carry?
About 9,168 vehicles per day (2023 count), of which roughly 20% are trucks.
How long is I 90 over Clark Fork River?
The structure is 982 ft (299.2 m) long with a longest span of 160 ft (48.8 m) and a deck 64 ft wide.
Who owns I 90 over Clark Fork River?
It is owned by the State Highway Agency.