S 1 over Boulder Creek
Granite County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- S 1 over Boulder Creek in Granite County, Montana, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1986, making it 39 years old at the 2025 inventory.
- It carries about 1,144 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 36 of the 73 inventoried bridges in Granite County rated fair (49.3%); 9 (12.3%) 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 2024, 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 → (46.47019, -113.23467)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 83 ft |
| Location | Maxville |
| NBI structure number | P00019049+00211 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Granite County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 90 over Harvey Creek | 1970 | 13,081 | Good |
| I 90 over Drainage | 1971 | 13,081 | Good |
| I 90 over Sep Bearmouth Road | 1970 | 13,081 | Good |
| I 90 over Clark Fork River | 1970 | 13,081 | Poor |
| I 90 over Rattler Gulch | 1971 | 13,081 | Fair |
| I 90 over Clark Fork River | 1970 | 11,802 | Fair |
All bridges nearby: Granite County, MT bridge conditions · every bridge in Granite County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.