Big Mound Rd over I-39 & US 51
Ogle County, Illinois · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Big Mound Rd over I-39 & US 51 in Ogle County, Illinois, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 1980, making it 45 years old at the 2025 inventory.
- It carries about 225 vehicles a day (traffic count year 2022).
- Its listed owner is the state highway agency.
- It is one of 178 of the 378 inventoried bridges in Ogle County rated good (47.1%); 28 (7.4%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated November 2023, on a 24-month routine inspection cycle.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (42.07885, -89.02237)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Continuous steel stringer or multi-beam girder |
| Length | about 256 ft |
| Location | 1.5 Mi S of Ill 72 |
| NBI structure number | 071005000000000 |
| Condition class | Good |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | November 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | N: not over a waterway |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Illinois department of transportation.
Busiest bridges in Ogle County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| I-39 & US 51 over Stream | 1981 | 32,800 | Fair |
| I 39 & US 51 over Kilbuck Creek Trib | 1981 | 32,800 | Fair |
| I-39 & US 51 over Stream | 1981 | 32,200 | Good |
| I-39 & US 51 over Stream | 1981 | 29,600 | Fair |
| I-39 & US 51 over Stream | 1981 | 29,600 | Fair |
| I-39 & US 51 over Stream | 1981 | 29,100 | Fair |
All bridges nearby: Ogle County, IL bridge conditions · every bridge in Ogle County · Illinois bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.