Structure 81574000000000 · Whatcom County, WA
Carries Mosquito Lk RD over Middle Fork, 05.2 SE Mt. Baker HWY.
431 ft end to end: about 6 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 through truss.
| State | Washington |
| County | Whatcom |
| Location | 05.2 SE Mt. Baker HWY |
| Carries | Mosquito Lk RD |
| Crosses | Middle Fork |
| Coordinates | 48.78462, -122.11314 |
| Material | Steel |
| Design | Truss - Thru |
| Total Length | 431.1 ft (131.4 m) |
| Max Span | 337.9 ft (103 m) |
| Deck Width | 16.1 ft (4.9 m) |
| Deck Area | 643.9 sq m |
| Main Spans | 1 |
| Year Built | 1915 (reconstructed 2010) |
| Avg Daily Traffic | 117 (2024) |
| Truck Traffic | 4% |
| Lanes On Bridge | 1 |
| Last Inspection | August 2024 |
| Inspection Frequency | Every 24 months |
| Owner | County Highway Agency |
| Historical Significance | Bridge is on the National Register of Historic Places |
| Scour Critical | 7 — Countermeasures installed |
| Structure Number | 081574000000000 |
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.