Mt 55 over Fish Creek
Jefferson County, Montana · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Mt 55 over Fish Creek in Jefferson County, Montana, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1953, making it 72 years old at the 2025 inventory.
- It carries about 1,858 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 7 of the 136 inventoried bridges in Jefferson County rated poor (5.1%); 7 (5.1%) are rated poor.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (45.7666, -112.18153)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 7 | Good condition |
| Superstructure | 4 | Poor condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Timber stringer or multi-beam girder |
| Length | about 38 ft |
| Location | 9M SW Whitehall |
| NBI structure number | P00055003+06271 |
| Condition class | Poor |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Jefferson County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 15 over Prickly Pear Creek | 1969 | 5,987 | Fair |
| I 15 over Prickly Pear Creek | 1969 | 5,987 | Fair |
| S 518 over Int Montana City-i 15 | 1968 | 5,885 | Good |
| I 90 over Int Cardwell-s 359 | 1968 | 5,599 | Fair |
| I 90 over Int Cardwell-s 359 | 1968 | 5,599 | Fair |
| I 90 Eastbound over Boulder River | 1968 | 5,599 | Good |
All bridges nearby: Jefferson County, MT bridge conditions · every bridge in Jefferson County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.