Structure 65000020 · Walworth County, SD
Carries IRR Us012 over Missouri Rv (oahe Lk), Corson - Walworth Co LN.
Set by its lowest-rated component: Superstructure and Substructure at 5 of 9.
How ratings work5,058 ft end to end, longest span 450 ft: about 14 football fields. 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 through truss.
| State | South Dakota |
| County | Walworth |
| Location | Corson - Walworth Co LN |
| Carries | IRR Us012 |
| Crosses | Missouri Rv (oahe Lk) |
| Coordinates | 45.56114, -100.46131 |
| Material | Steel Continuous |
| Design | Truss - Thru |
| Total Length | 5058.4 ft (1541.8 m) |
| Max Span | 449.8 ft (137.1 m) |
| Deck Width | 28.5 ft (8.7 m) |
| Deck Area | 13413.7 sq m |
| Main Spans | 5 |
| Year Built | 1959 (reconstructed 1980) |
| Avg Daily Traffic | 2,071 (2024) |
| Truck Traffic | 12% |
| Lanes On Bridge | 2 |
| Last Inspection | September 2024 |
| Inspection Frequency | Every 12 months |
| Owner | State Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Scour Critical | 5 — Stable for scour |
| Structure Number | 000000065000020 |
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.