Structure 11607000000086 · Mineral County, MT
Carries RD 431 over ST Regis River, Twomile CR.
151 ft end to end, longest span 94 ft: about 2 semi-trucks nose to tail. Lengths and the semi-truck on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.
| State | Montana |
| County | Mineral |
| Location | Twomile CR |
| Carries | RD 431 |
| Crosses | ST Regis River |
| Coordinates | 47.29557, -115.16934 |
| Material | Steel |
| Design | Stringer/Multi-beam |
| Total Length | 150.9 ft (46 m) |
| Max Span | 94.2 ft (28.7 m) |
| Deck Width | 18.0 ft (5.5 m) |
| Deck Area | 253 sq m |
| Main Spans | 3 |
| Year Built | 1957 |
| Avg Daily Traffic | 50 |
| Lanes On Bridge | 1 |
| Last Inspection | May 2023 |
| Inspection Frequency | Every 24 months |
| Owner | U.S. Forest Service |
| Historical Significance | Historical significance is not determined |
| Scour Critical | 5 — Stable for scour |
| Structure Number | 011607000000086 |
Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."
A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.