Ill 75 over Rock River
FairWinnebago County, Illinois · In Rockton · Structure no. 101010900000000
- Built
- 1927
- 98 years old, rebuilt 1974
- Condition
- Fair
- inspected June 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete Continuous
- Length
- 568 ft
- 8 main spans
- Daily traffic
- 7,200
- 2023 count
- Owner
- State
- State Highway Agency
About this bridge
Ill 75 over Rock River is a prestressed concrete continuous stringer/multi-beam or girder carrying Ill 75 over Rock River in Winnebago County, Illinois. It was built in 1927 and reconstructed in 1974, so it is 98 years old, older than the Illinois average of 45.3 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 7,200 vehicles a day, roughly 8% of them trucks, projected to reach 7,828 by 2046. The structure is 568 ft (173.2 m) long and 39 ft wide. If it were closed, the detour would be 1.9 mi (3 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Superstructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Substructure | 5 Fair | All primary structural elements are sound but may have minor section loss, cracking, spalling or scour. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was Ill 75 over Rock River built?
It was built in 1927, making it 98 years old in 2025. It was reconstructed in 1974.
What condition is Ill 75 over Rock River in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in June 2024.
How much traffic does Ill 75 over Rock River carry?
About 7,200 vehicles per day (2023 count), of which roughly 8% are trucks.
How long is Ill 75 over Rock River?
The structure is 568 ft (173.2 m) long with a longest span of 71 ft (21.6 m) and a deck 39 ft wide.
Who owns Ill 75 over Rock River?
It is owned by the State Highway Agency.