Iroquois County, IL

565 public highway bridges

Iroquois County Bridge Snapshot

Iroquois County, Illinois contains 565 public highway bridges in the FHWA National Bridge Inventory. Roughly 46% are rated “Good,” 35.8% “Fair,” 13.3% “Poor,” and 13.3% are classified as structurally deficient — the federal designation for spans whose deck, superstructure, or substructure has been rated 4 or below on the 0–9 NBI scale. Structurally deficient does not mean unsafe to cross; it means the bridge is on the priority list for repair or replacement.

Inspections in IL are conducted by certified engineers from the state Department of Transportation on a 24-month cycle, and results are reported back to the FHWA each spring. The list below shows every NBI-tracked bridge in the county, sorted by inventory load rating. Use the “Sort by” controls to surface the lowest-rated spans first, and click any row for full inspection history, traffic counts, and condition trends.

Source: FHWA National Bridge Inventory. See methodology for full definitions.

565

Total Bridges

46%

Good

13.3%

Poor

13.3%

Structurally Deficient

Condition Distribution

Good

46% (260)

Fair

35.8% (202)

Poor

13.3% (75)

SD

13.3% (75)

All Bridges (565)

Sort:

FAI-57 NB

Over: WEST SECOND ST

8.63 MI S ASHKUM INT, Iroquois, IL

Built 1967 ADT: 450

FAI-57 SB

Over: WEST SECOND ST

8.6 MI S ASHKUM INT, Iroquois, IL

Built 1967 ADT: 450

FAI-57 NB

Over: FAS 317 & ICG RR

0.78 MI S CLIFTON IN, Iroquois, IL

Built 1966 ADT: 1,750

FAI-57 SB

Over: FAS 317 & ICG RR

0.78 M S CLIFTON INT, Iroquois, IL

Built 1966 ADT: 1,750

CSX TRANS INC.

Over: IL 1/FAP 332A

N EDGE MILFORD RR BR, Iroquois, IL

Built 1939 ADT: 2,450

US 24

Over: I 57

GILMAN INTERCHANGE, Iroquois, IL

Built 1967 ADT: 18,100

ILL 54

Over: I 57

ONARGA INTERCHANGE, Iroquois, IL

Built 1967 ADT: 16,400

DANFORTH RD FAS 33

Over: I-57

4.59 MI S OF ILL 116, Iroquois, IL

Built 1967 ADT: 18,100

FAS 334 /C.H.9

Over: FAI 57

BUCKLEY INTERCHANGE, Iroquois, IL

Built 1968 ADT: 17,500

FAS 335W/CH 10

Over: FAI 57

6.45 M S BUCKLEY INT, Iroquois, IL

Built 1968 ADT: 17,600

CH 47 / 1200 N Rd

Over: FAI-57

2.62 MI S ONARGA INT, Iroquois, IL

Built 1968 ADT: 17,500

TR 155

Over: I-57

2.0 Mi N of US 24, Iroquois, IL

Built 1967 ADT: 18,100

CH 29

Over: I-57

3.0 M S OF CHEB INTR, Iroquois, IL

Built 1965 ADT: 19,100

K3,BEAVERVILLE & S

Over: US 52

8.28 MI E OF ILL 1, Iroquois, IL

Built 1935 ADT: 1,300

ILL 116 ASHKUM INT

Over: I 57

ASHKUM INTER, Iroquois, IL

Built 1967 ADT: 18,400

TR 89

Over: I 57

2.47 MI S ASHKUM INT, Iroquois, IL

Built 1967 ADT: 18,100

TR 26A

Over: I-57

7.11 MI S ONARGA INT, Iroquois, IL

Built 1968 ADT: 17,500

TWP RD 35

Over: I 57

4.27 M S CHEBANSE IT, Iroquois, IL

Built 1965 ADT: 19,100

TWP RD 49A

Over: I 57

1.59 MI S CLIFTON IN, Iroquois, IL

Built 1966 ADT: 18,400

TR 58A

Over: I 57

1.17 MI S GILMAN INT, Iroquois, IL

Built 1967 ADT: 16,400

TWP RD 95

Over: I 57

3.48 M S OF ILL 116, Iroquois, IL

Built 1967 ADT: 18,100

TWP RD 109

Over: I 57

5.59 MI S ASHKUM INT, Iroquois, IL

Built 1967 ADT: 18,100

TWP RD 269

Over: I-57

4.67 MI S ONARGA INT, Iroquois, IL

Built 1968 ADT: 17,500

TWP RD 327

Over: FAI 57

1.07 MI S BUCKLEY IN, Iroquois, IL

Built 1968 ADT: 17,600

TR 349

Over: FAI 57

4.1 M S BUCKLEY INTR, Iroquois, IL

Built 1968 ADT: 17,600

FAS 321 (CH 4)

Over: I-57

CLIFTON INTER, Iroquois, IL

Built 1965 ADT: 19,100

FAS 1322 (CH 37)

Over: I-57

CHEBANSE INT, Iroquois, IL

Built 1965 ADT: 19,400

KB&S RR

Over: TR 91A

1.5MI SE DONOVAN, Iroquois, IL

Built 1900 ADT: 75

TR 168

Over: WHISKEY CR

1.1 MI S. CH 10, Iroquois, IL

Built 1929 Load: 9.4 t ADT: 25

TR 251F

Over: JEFFERSON CREEK

3.3 MI S OF WOODLAND, Iroquois, IL

Built 1938 Load: 12.6 t ADT: 425

TR 312

Over: STREAM

2.5 MI E PITTWOOD, Iroquois, IL

Built 1954 Load: 16.8 t ADT: 50

TR 196

Over: TRIB. TO IROQ. RIVER

1MI S. SUGAR ISLANDE, Iroquois, IL

Built 1915 Load: 17.8 t ADT: 250

TR 345A

Over: TRIB TO SPRING CR

.5 MI E OF US 45, Iroquois, IL

Built 1916 Load: 21.1 t ADT: 50

TR 340

Over: IROQUOIS RIVER

1.25 MI N. US 24, Iroquois, IL

Built 1912 Load: 23.0 t ADT: 200

TR-343

Over: Trib. to Mud Creek

3 MI E. ILL RTE 1, Iroquois, IL

Built 1965 Load: 23.0 t ADT: 50

TR 28

Over: PRAIRIE CR

3 MI NW GILMAN, Iroquois, IL

Built 1939 Load: 23.7 t ADT: 50

TR 15

Over: TRIB LANGAN CREEK

1.8MI E CH8, Iroquois, IL

Built 1929 Load: 23.7 t ADT: 25

TR 99B

Over: MIDDLEPORT DITCH #1

1 MI E. ILL 1, Iroquois, IL

Built 1968 Load: 24.0 t ADT: 75

TR 100

Over: TRIB TO PIGEON CR

4.2MI S CH44, Iroquois, IL

Built 1975 Load: 24.0 t ADT: 50

FAS 1335 CH 42

Over: TRIB LITTLE MUD CR

1.2MI N JCT CH44+42, Iroquois, IL

Built 1925 Load: 24.3 t ADT: 150

TR 2C

Over: BEAVER CR

ILL-IND STATE LN, Iroquois, IL

Built 1968 Load: 24.3 t ADT: 100

TR 237

Over: DRAINAGE DITCH

3.5SE WOODLAND, Iroquois, IL

Built 1910 Load: 24.3 t ADT: 25

TR 2 D

Over: STREAM

0.2 Mi S of CR1400S, Iroquois, IL

Built 1953 Load: 24.3 t ADT: 75

TR 363A

Over: TRIB FOUNTAIN CR

3MI E FOUNTAIN CR, Iroquois, IL

Built 1937 Load: 24.3 t ADT: 125

CH 42

Over: SPRING CREEK

2.2MI S US24, Iroquois, IL

Built 1977 Load: 24.6 t ADT: 75

FAS 325

Over: DRAIN DT

2.91 MI S OF ILL 1, Iroquois, IL

Built 1958 Load: 25.3 t ADT: 1,150

TR 336A

Over: STREAM

3 MI SE MILFORD, Iroquois, IL

Built 1970 Load: 25.3 t ADT: 50

FAS 337

Over: TRIB SPRING CREEK

1MI E THAWVILLE, Iroquois, IL

Built 1969 Load: 25.6 t ADT: 150

FAS 329 CH 10 SA 1

Over: FOUNTAIN CREEK

5.06 MI E OF ILL 49, Iroquois, IL

Built 1958 Load: 25.9 t ADT: 500

CH 9 FAS 334

Over: SPRING CR

1 MI E JCT CH9 US45, Iroquois, IL

Built 1952 Load: 25.9 t ADT: 500

Read our methodology — how this data is sourced, computed, and verified.

Related

Browse all → | Rankings →

Data sourced from official U.S. government datasets. See our methodology for details. Retrieved and formatted by PlainBridges Editorial

Reviewed byPlainbridges Editorial, Plain Bridges Editorial Team · June 6, 2026