Hwy 91 N over Big Hole River 041
Beaverhead County, Montana · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Hwy 91 N over Big Hole River 041 in Beaverhead County, Montana, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 4 (poor condition) on the 0-9 scale.
- It was built in 1940, making it 85 years old at the 2025 inventory.
- It carries about 158 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 24 of the 227 inventoried bridges in Beaverhead County rated poor (10.6%); 24 (10.6%) are rated poor.
- Its traffic status in the 2025 inventory is closed to all traffic (NBI item 41).
- Its class is unchanged from 2024 (poor), but component ratings moved: substructure 6 to 4.
- Status change: newly closed since 2024.
- Its most recent inspection on record is dated July 2024, on a 24-month routine inspection cycle.
- It has fracture-critical members (NBI item 92A): steel tension members without a redundant load path, which get their own scheduled inspections.
- 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 → (45.52664, -112.70197)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 4 | 4 | Poor condition |
| Superstructure | 4 | 4 | Poor condition |
| Substructure | 6 | 4 | Poor condition |
Bridge details
| Structure | Steel through truss |
| Length | about 239 ft |
| Location | 22M N Dillon |
| NBI structure number | L01311022+02001 |
| Condition class | Poor |
| Traffic status (item 41) | Closed to all traffic |
| Last inspection (item 90) | July 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
| Fracture critical (item 92A) | Yes |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Montana department of transportation.
Busiest bridges in Beaverhead County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| S 89 over Local-blacktail Cr-rr | 1974 | 4,241 | Fair |
| S 89 over Int North Dillon I 15 | 1973 | 4,241 | Fair |
| I 15 over Drainage Irr Ditch | 1973 | 3,915 | Fair |
| I 15 over Birch Creek | 1973 | 3,852 | Fair |
| I 15 over Int Jackson-hwy 278 | 1982 | 2,863 | Fair |
| I 15 over Int Jackson-hwy 278 | 1982 | 2,863 | Good |
All bridges nearby: Beaverhead County, MT bridge conditions · every bridge in Beaverhead County · Montana bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.