S 1 over Clark Fork
PoorGranite County, Montana · Drummond · Structure no. P00019063+02511
- Built
- 1966
- 59 years old
- Condition
- Poor
- inspected May 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 301 ft
- 5 main spans
- Daily traffic
- 1,354
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
S 1 over Clark Fork is a prestressed concrete stringer/multi-beam or girder carrying S 1 over Clark Fork in Granite County, Montana. It was built in 1966, so it is 59 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 3 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 1,354 vehicles a day, roughly 2% of them trucks, projected to reach 1,456 by 2043. The structure is 301 ft (91.7 m) long and 32 ft wide. If it were closed, the detour would be 29.8 mi (48 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 | 6 Satisfactory | Structural elements show some minor deterioration. |
| Superstructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Substructure | 3 Serious | Loss of section, deterioration, spalling or scour have seriously affected primary structural components. |
| 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 S 1 over Clark Fork built?
It was built in 1966, making it 59 years old in 2025.
What condition is S 1 over Clark Fork 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 May 2024.
How much traffic does S 1 over Clark Fork carry?
About 1,354 vehicles per day (2023 count), of which roughly 2% are trucks.
How long is S 1 over Clark Fork?
The structure is 301 ft (91.7 m) long with a longest span of 61 ft (18.6 m) and a deck 32 ft wide.
Who owns S 1 over Clark Fork?
It is owned by the State Highway Agency.