Gillespie Slideroc over Clark Fork
Missoula County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Gillespie Slideroc over Clark Fork in Missoula County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1965, making it 60 years old at the 2025 inventory.
- It carries about 50 vehicles a day.
- It is one of 125 of the 206 inventoried bridges in Missoula County rated fair (60.7%); 15 (7.3%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated July 2023, on a 24-month routine inspection cycle.
- A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.
View this bridge on a map → (46.72145, -113.5713)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 212 ft |
| Location | Gillespie-sliderock |
| NBI structure number | 011603000000076 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 4: foundations stable, field review says exposed foundations need protection |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Missoula County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| N Reserve St over Clark Fork R Flood Plain | 1977 | 35,914 | Fair |
| N Reserve St over Clark Fork River | 1975 | 35,914 | Fair |
| Reserve St over W Broadway St-rr | 1998 | 29,572 | Fair |
| Brooks St-us 12 over Bitterroot River | 1968 | 28,185 | Fair |
| I 90 over Grant Creek | 1965 | 27,328 | Good |
| N Russel Street over Clark Fork River | 2020 | 23,274 | Good |
All bridges nearby: Missoula County, MT bridge conditions · every bridge in Missoula County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.