I-39 Sb/us 51SB over C & NW RR
LaSalle County, Illinois · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- I-39 Sb/us 51SB over C & NW RR in LaSalle County, Illinois, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- It was built in 1977, making it 48 years old at the 2025 inventory.
- It carries about 9,350 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (41.47649, -89.04952)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 6 | Satisfactory condition |
| Superstructure | 4 | Poor condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Prestressed concrete stringer or multi-beam girder |
| Length | about 175 ft |
| Location | 0.21 Mi N of US 52 |
| NBI structure number | 050016700000000 |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Illinois department of transportation.
All bridges nearby: LaSalle County, IL bridge conditions · Illinois bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.