Main Boulder Rd over Boulder River 040
Park County, Montana · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Main Boulder Rd over Boulder River 040 in Park 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 1938, making it 87 years old at the 2025 inventory.
- It carries about 157 vehicles a day (traffic count year 2023).
- Its listed owner is the county highway agency.
- It is one of 86 of the 126 inventoried bridges in Park County rated fair (68.3%); 13 (10.3%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated September 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 → (45.33569, -110.23121)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 85 ft |
| Location | 31M S Springdale |
| NBI structure number | L34210000+08001 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | September 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Park County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I 90 over Int West Livingston | 1962 | 9,461 | Fair |
| I 90 over Int West Livingston | 1962 | 9,461 | Fair |
| I 90 over Int S Livingston-us Hwy | 1962 | 9,461 | Fair |
| I 90 over Quinn Creek Road | 2022 | 8,272 | Good |
| I 90 over Quinn Creek Road | 2022 | 8,272 | Good |
| I 90 over Int Hopper | 1978 | 8,236 | Fair |
All bridges nearby: Park County, MT bridge conditions · every bridge in Park County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.