US Bridges

Il 120 over Fox River

Fair

McHenry County, Illinois · Mchenry · Structure no. 056004900000000

Built
1985
40 years old
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
431 ft
5 main spans
Daily traffic
18,100
2023 count
Owner
State
State Highway Agency

About this bridge

Il 120 over Fox River is a steel continuous stringer/multi-beam or girder carrying Il 120 over Fox River in McHenry County, Illinois. It was built in 1985, so it is 40 years old, younger 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 6 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 18,100 vehicles a day, roughly 9% of them trucks, projected to reach 23,160 by 2046. The structure is 431 ft (131.4 m) long and 76 ft wide.

Location

Open in Google Maps
CarriesIl 120
CrossesFox River
LocationMchenry
RouteState Highway 120
CountyMcHenry County
StateIllinois
Coordinates42.34431, -88.26163
Functional classUrban Other Principal Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating95 US tons
Inventory rating57.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length431 ft (131.4 m)
Longest span110 ft (33.5 m)
Deck width76 ft (23.2 m)
Roadway width48 ft (14.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic18,100 (2023)
Projected traffic23,160 by 2046
Trucks9%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was Il 120 over Fox River built?

It was built in 1985, making it 40 years old in 2025.

What condition is Il 120 over Fox 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 May 2024.

How much traffic does Il 120 over Fox River carry?

About 18,100 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is Il 120 over Fox River?

The structure is 431 ft (131.4 m) long with a longest span of 110 ft (33.5 m) and a deck 76 ft wide.

Who owns Il 120 over Fox River?

It is owned by the State Highway Agency.