Structure 11607000000070 · Mineral County, MT
Carries RD 352 over Twelvemile Creek, Henderson-thompson.
Set by its lowest-rated component: Deck and Substructure at 5 of 9.
How ratings work24 ft end to end. Lengths are drawn to scale; at this length a semi-truck would be a speck. 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 | Henderson-thompson |
| Carries | RD 352 |
| Crosses | Twelvemile Creek |
| Coordinates | 47.44683, -115.24190 |
| Material | Wood or Timber |
| Design | Stringer/Multi-beam |
| Total Length | 23.6 ft (7.2 m) |
| Max Span | 22.0 ft (6.7 m) |
| Deck Width | 15.1 ft (4.6 m) |
| Deck Area | 33.1 sq m |
| Main Spans | 1 |
| Year Built | 1955 |
| Avg Daily Traffic | 50 |
| Lanes On Bridge | 1 |
| Last Inspection | July 2023 |
| Inspection Frequency | Every 24 months |
| Owner | U.S. Forest Service |
| Historical Significance | Historical significance is not determined |
| Scour Critical | 4 — Foundations need monitoring |
| Structure Number | 011607000000070 |
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.