Old Darby RD over Rock Creek 052
Fair Condition108 years old100 vehicles/day
Location
| State | Montana |
| County | Ravalli |
| Location | 4m N Darby |
| Carries | Old Darby RD |
| Crosses | Rock Creek 052 |
| Coordinates | 46.08221, -114.17516 |
Condition Ratings
| Overall Condition | Fair |
| Deck | 5 (Fair) |
| Superstructure | 6 (Satisfactory) |
| Substructure | 6 (Satisfactory) |
| Channel/Waterway | 8 (Very Good) |
| Scour Critical | 5 — Stable for scour |
Physical Characteristics
| Material | Steel |
| Design | Stringer/Multi-beam |
| Total Length | 61.0 ft (18.6 m) |
| Max Span | 27.9 ft (8.5 m) |
| Deck Width | 16.1 ft (4.9 m) |
| Deck Area | 91.1 sq m |
| Main Spans | 2 |
| Year Built | 1918 (reconstructed 1936) |
Traffic
| Avg Daily Traffic | 100 (2025) |
| Truck Traffic | 3% |
| Lanes On Bridge | 1 |
Inspection & Ownership
| Last Inspection | 823 |
| Inspection Frequency | Every 24 months |
| Owner | County Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Structure Number | L41703003+05001 |