300-1 over St Regis River
Mineral County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 300-1 over St Regis River in Mineral County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1955, making it 70 years old at the 2025 inventory.
- It carries about 50 vehicles a day.
- It is one of 99 of the 153 inventoried bridges in Mineral County rated fair (64.7%); 17 (11.1%) are rated poor.
- 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 → (47.35822, -115.311)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 5 | Fair condition |
| Superstructure | 6 | Satisfactory condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Steel girder and floorbeam |
| Length | about 124 ft |
| Location | St Regis River |
| NBI structure number | 011607000001052 |
| Condition class | Fair |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Mineral County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 90 over Drainage | 1986 | 8,111 | Good |
| I 90 over Sep Local Road | 1973 | 7,824 | Fair |
| I 90 over Sep Local Road | 1973 | 7,824 | Fair |
| I 90 over Int Taft | 1973 | 7,824 | Fair |
| I 90 over Sep Randolph Creek Road | 1973 | 7,824 | Fair |
| I 90 over St. Regis River | 1973 | 7,824 | Fair |
All bridges nearby: Mineral County, MT bridge conditions · every bridge in Mineral County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.