How many bridges are in Illinois?

Illinois has 27,743 public highway bridges tracked in the FHWA National Bridge Inventory. View detailed condition data for each bridge on PlainBridges.

What percentage of bridges in Illinois are structurally deficient?

7.9% of bridges in Illinois are classified as structurally deficient by the FHWA, compared to a national average of 7.0%.

State profile · Near national median SD

Illinois bridge safety

Condition ratings, load ratings, and structural-deficiency data for every public highway bridge in Illinois — drawn straight from the FHWA National Bridge Inventory.

Reviewed byPlainbridges Editorial, Plain Bridges Editorial Team · June 7, 2026

27,743
Public bridges: 41.2%
Good condition: 7.9%
Poor condition: 7.9%
Structurally deficient

Total Bridges

27,743

Public highway bridges in Illinois

Good Condition

41.2%

11,426 bridges rated 7-9

-8.8pp vs 50% benchmark

Poor Condition

7.9%

2,186 bridges rated 0-4

Structurally Deficient

7.9%

2,186 bridges flagged for repair priority

0.9pp vs national avg 7.0%

Illinois vs national bridge condition

Illinois — Good condition share 41.2%

National avg

Share of bridges rated 7-9 on the FHWA 0-9 scale (deck, superstructure, substructure all good).

Illinois — Structurally deficient share 26.3%

National avg

Lower is better. Bar maxes at 30% (worst-state ceiling). National average sits at 7.0%.

Condition Distribution

Bridge inventory deck-condition mix — Illinois (FHWA NBI)

Counties (102)

Adams 325 Alexander 96 Bond 165 Boone 111 Brown 71 Bureau 382 Calhoun 81 Carroll 185 Cass 77 Champaign 743 Christian 323 Clark 232 Clay 171 Clinton 187 Coles 308 Cook 2185 Crawford 196 Cumberland 169 De Witt 197 DeKalb 264 Douglas 234 DuPage 380 Edgar 278 Edwards 79 Effingham 260 Fayette 356 Ford 300 Franklin 323 Fulton 210 Gallatin 82 Greene 166 Grundy 269 Hamilton 164 Hancock 291 Hardin 58 Henderson 144 Henry 331 Iroquois 565 Jackson 235 Jasper 180 Jefferson 270 Jersey 111 Jo Daviess 198 Johnson 120 Kane 354 Kankakee 352 Kendall 133 Knox 321 LaSalle 529 Lake 286 Lawrence 183 Lee 372 Livingston 578 Logan 296 Macon 368 Macoupin 248 Madison 543 Marion 301 Marshall 153 Mason 85 Massac 138 McDonough 210 McHenry 229 McLean 624 Menard 90 Mercer 162 Monroe 130 Montgomery 261 Morgan 241 Moultrie 171 Ogle 377 Peoria 365 Perry 139 Piatt 249 Pike 338 Pope 86 Pulaski 106 Putnam 50 Randolph 155 Richland 147 Rock Island 256 Saline 176 Sangamon 480 Schuyler 121 Scott 96 Shelby 330 St. Clair 502 Stark 89 Stephenson 332 Tazewell 361 Union 192 Vermilion 515 Wabash 88 Warren 202 Washington 232 Wayne 264 White 210 Whiteside 280 Will 674 Williamson 204 Winnebago 475 Woodford 222

Illinois vs nearby ranks

Adjacent states on the structurally deficient leaderboard (lower share = better)

States are ranked by share of bridges flagged structurally deficient — the FHWA classification for any span where deck, superstructure, or substructure carries a condition rating of 4 or below. Lower percentages indicate stronger maintenance funding and inspection follow-through. States here sit immediately above and below Illinois on the same metric.

Rhode Island

7.69% top marginal rate

Structure: Progressive
Burden @ $100K: $78

Nebraska

7.73% top marginal rate

Structure: Progressive
Burden @ $100K: $15,571

Selected

Illinois

7.88% top marginal rate

Structure: Progressive
Burden @ $100K: $27,743

Massachusetts

7.96% top marginal rate

Structure: Progressive
Burden @ $100K: $5,314

Missouri

8.53% top marginal rate

Structure: Progressive
Burden @ $100K: $24,654

Bridges Needing Most Attention in Illinois

Six lowest-condition bridges in Illinois, ranked by composite NBI rating. Each is inspected at least every 24 months.

FAS 1599

Poor

Over: DRAINAGE CANAL

2.2 MI E MEYER, Adams, IL

Built 1980 Load: 0.6 t ADT: 200

CH 15

Poor

Over: E FK MAZONRIVER

0.05 MI W CH 16, Grundy, IL

Built 1977 Load: 1.0 t ADT: 1,400

MOOSE RD - TR 240

Structurally Deficient

Over: WILSON CREEK

NE-35-T3NR2E, Fulton, IL

Built 1935 Load: 1.3 t ADT: 10

TR 10-B

Structurally Deficient

Over: KING CREEK

W EDGE OF MINERAL, Bureau, IL

Built 1899 Load: 1.6 t ADT: 10

TR-6

Structurally Deficient

Over: DRAINAGE DITCH

3.5 MI NE DIETERICH, Effingham, IL

Built 1909 Load: 1.6 t ADT: 25

TR208K(TWIN BRIDGE

Structurally Deficient

Over: BIG CREEK

NE EDGE MT ZION, Macon, IL

Built 1967 Load: 1.9 t ADT: 375

All Bridges in Illinois

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Publisher	Kiznis Studio
Sources	FHWA National Bridge Inventory, public U.S. government datasets

Illinois vs national bridge condition

Condition Distribution

Counties (102)

Bridges Needing Most Attention in Illinois

FAS 1599

CH 15

MOOSE RD - TR 240

TR 10-B

TR-6

TR208K(TWIN BRIDGE

All Bridges in Illinois

FAI 280 WB

27TH ST - MOLINE

IL 92 SB (CENT FRW

IL 92 NB (CENT FRW

IL 5 WB (J DEERE R

IL 5 EB (J DEERE R

IL 5 WB (J DEERE R

IL 5 EB (J DEERE R

23RD AVE-MOLINE

27TH ST SB-MOLINE

19TH ST NB-MOLINE

FAI 74 SB

FAI 74 NB

MOLINE RD (FAS 120

226 ST N

248 ST N

265 ST N CH 4

FAS 1204 ILL 92

CH 25

TR 232 /300 TH ST

PORT BYRON RD

317TH ST N

122ND AVE N

PEDESTRIAN WALKWAY

IL 5 WB (J DEERE R

I-280 EB

I-280 WB

PEDESTRIAN OVERPAS

MILAN BELTWAY

MILAN BELTWAY

52ND AVE

FAI 74 SB

27TH ST. - MOLINE

IL 5/IL 92

ILL 92

ILL 92 S.B.

ILL 92 N.B.

41ST ST. CONNECTOR

I 74 NB

I 74 SB

I-74 WB

I-74 N.B. OFF RAMP

I-74 NB WB(NB)

I-74 EB (SB)

FAI 74 WB

FAI 74 EB

RAMP6THC

RAMP 6TH D

IL 92 SB (CENT FRW

IL 92 NB (CENT FRW

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