County profile · official public datasets

McLean County, IL

624 public highway bridges tracked in the FHWA National Bridge Inventory: 60.9% rated Good, 36.2% Fair, 2.9% Poor.

624
Public bridges
60.9%
Good condition
2.9%
Poor condition

The verdict

According to the Federal Highway Administration's 2024 National Bridge Inventory.

McLean County posts a top-10% lowest Poor-condition share among rated counties in the state across large county bridge inventory.

Top 6%
lowest Poor share in state
2.9%
Poor-condition share
624
public highway bridges
1981
avg year built

Poor is an FHWA condition category from the lowest applicable component rating (4 or below), not a live crossing-safety or closure decision. Rankings cover counties with at least five public highway bridges.

McLean County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, McLean County ranks #6 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 2.9%). McLean County, Illinois contains 624 public highway bridges. Roughly 60.9% are rated “Good,” 36.2% “Fair,” and 2.9% “Poor.” Poor means the lowest applicable deck, superstructure, substructure, or culvert rating is 4 or below on the 0–9 NBI scale. It is a condition category, not a live safety or closure decision.

Responsible agencies inspect covered bridges on risk-based intervals under current NBIS rules and submit inventory data to FHWA annually. The list below shows every NBI-tracked bridge in the county. Use the “Sort by” controls to change the ordering, and click any row for its reported inspection date, traffic count, and condition fields.

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

Total bridges

624

Public highway bridges in McLean County

Good condition

60.9%

380 of 624 rated 7-9

Fair condition

36.2%

226 of 624 rated 5-6

Poor condition

2.9%

18 of 624 rated 4 or below

In-state Poor-share rank

#6 of 102

Among Illinois counties with 5+ bridges, lower share ranks better

Condition distribution

Share of 624 NBI-tracked bridges by lowest applicable component rating.

Good
60.9% (380)
Fair
36.2% (226)
Poor
2.9% (18)

McLean County's Poor-condition bridges carry 69,775 vehicle crossings a day

That is 3.7% of the county's reported daily bridge traffic on 2.9% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 3,876 crossings a day against 1,624 for a Good-condition one. A Poor rating is a condition category, not a closure or a live safety judgement; it means the lowest applicable component rating is 4 or below.

Computed over the 624 of 624 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

39.7% of McLean County's bridges have passed the 50-year mark

248 of the 624 bridges with a recorded construction year were built in 1974 or earlier. Age alone is not a defect: a well-maintained older bridge can rate Good, and 60.9% of this county's inventory does. Even so, this older cohort is the population from which future Poor ratings are drawn, which is why the age profile below matters alongside the condition split above.

Cutoff derives from the 2024 release year minus a 50-year design life. Source: FHWA National Bridge Inventory, 2024 release.

One structure carries 35.8% of the county's Poor-condition bridge traffic

I-55 BUSN LOOP over Norfolk Southern Railway, built 1940, carries 25,000 vehicles a day, the most of any Poor-rated structure here. The county's Poor-condition exposure is concentrated rather than evenly spread, so the 18-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 69,775 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When McLean County's bridges were built

624 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1960s, when 131 of the county's bridges still in the inventory were built, which is 21% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1981) matches the Illinois average (1979).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

How McLean County compares with Illinois's closest counties by inventory size

The 5 Illinois counties nearest McLean County in number of bridges, with their condition splits. Its 2.9% Poor share is the 1st-lowest of these 6. Its average build year of 1981 against a peer-group mean of 1980 is in line with the group.

Showing the 5 closest of 101 Illinois counties eligible for comparison.

Bridge inventory size and condition shares for McLean County and the 5 Illinois counties closest to it in inventory size
County Bridges Poor
Will County 649 10.5%
McLean County (this page) 624 2.9%
Livingston County 579 8.3%
Iroquois County 570 14.4%
LaSalle County 528 12.3%
Madison County 523 8.4%

Each share is of that county's own total tracked bridges; peers are the counties with 5 or more bridges whose inventory size is closest to McLean County's. Source: FHWA National Bridge Inventory, 2024 release.

Nationwide counties with similar inventory size or average build year

Two NBI-derived peer sets for McLean County, both outside Illinois so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside IL (624 bridges here).

Similar average build year

Nearest mean year-built outside IL (1981 here).

Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.

All 624 Good 380 Fair 226 Poor 18

Fair-condition bridges (226)

US 136

Fair

Over: MUD CREEK

2.09 M W OF US 51, McLean, IL

Built 2009 Load: 48.6 t ADT: 3,000

FAP 730 US 51

Fair

Over: PEDESTRIAN WALKWAY

1.93 MI SO OF I-55, McLean, IL

Built 1983 Load: 48.9 t ADT: 23,500

I-55/I-74 NB

Fair

Over: College Ave(FAU6352)

3.5 MI SW OF RT 51, McLean, IL

Built 1999 Load: 49.2 t ADT: 21,050

I-55/I-74 SB

Fair

Over: College Ave(FAU6352)

3.5 M SW OF RT 51, McLean, IL

Built 1999 Load: 49.2 t ADT: 21,050

I-74/WB

Fair

Over: Norfolk Southern Railway

12.3 MI E OF ILL 117, McLean, IL

Built 1964 Load: 50.5 t ADT: 14,800

I-74/EB

Fair

Over: Norfolk Southern Railway

12.3 MI E OF ILL 117, McLean, IL

Built 1964 Load: 50.5 t ADT: 14,800

ILL 54

Fair

Over: STREAM

4.25 M N OF US 136, McLean, IL

Built 1934 Load: 50.5 t ADT: 900

IL 9 & US 150

Fair

Over: Union Pacific Railroad

1 MI E I55/74, McLean, IL

Built 1996 Load: 50.5 t ADT: 6,100

MS-6743 (BELT AVE)

Fair

Over: SUGAR CREEK

1.3 MI NW 55 & 9, McLean, IL

Built 1950 Load: 50.5 t ADT: 225

I-55/I-74 SB

Fair

Over: Union Pacific Railroad

2.4 MI S JT I55 ILL9, McLean, IL

Built 1963 Load: 52.2 t ADT: 21,550

I-55/I-74 SB

Fair

Over: SUGAR CREEK

1.0 MI S JCT ILL 9, McLean, IL

Built 1963 Load: 52.2 t ADT: 21,550

I-55/I-74 NB

Fair

Over: SUGAR CREEK

1.0 MI SO I55 &ILL 9, McLean, IL

Built 1963 Load: 52.2 t ADT: 21,550

FAS 473 CH 8

Fair

Over: TURKEY CREEK

W EDGE LEXINGTON, McLean, IL

Built 1946 Load: 52.8 t ADT: 2,750

I-55/I-74 SB

Fair

Over: SIX PTS.RD/FAU 6369

1.9 MI S JCT ILL 9, McLean, IL

Built 1963 Load: 54.4 t ADT: 21,550

I-55 NW BLOOMINGTO

Fair

Over: I-74

I-55NB OVER I-74, McLean, IL

Built 1962 Load: 54.4 t ADT: 18,850

US 136

Fair

Over: SMALL STREAM

4.9 M E OF ILL 54, McLean, IL

Built 1933 Load: 57.7 t ADT: 1,700

ILL 9

Fair

Over: I-55/I-74

INTERCHANGE ILL 9, McLean, IL

Built 1964 Load: 58.6 t ADT: 19,100

FAS 1488/OLD RT 66

Fair

Over: TIMBER CREEK

4.5 MI NE OF US 136, McLean, IL

Built 2015 Load: 59.3 t ADT: 1,200

I-39/US 51 NB

Fair

Over: W BR SUGAR CREEK

S OF I-55/I-39 JCT., McLean, IL

Built 1988 Load: 63.2 t ADT: 6,750

I-55/I-74 NB

Fair

Over: NS Railway & White Oak R

3.8 MI SW OF RT 51, McLean, IL

Built 1963 Load: 64.2 t ADT: 21,050

I-55/I-74 SB

Fair

Over: NS Railway & White Oak R

3.8 M SW OF RT 51, McLean, IL

Built 1963 Load: 64.2 t ADT: 21,050

ILL 9

Fair

Over: SUGAR CREEK

0.48 MI E OF FAI 55, McLean, IL

Built 1980 Load: 73.9 t ADT: 16,000

I-74 WB

Fair

Over: KICKAPOO CR

5.93 MI E OF US 51, McLean, IL

Built 1968 Load: 78.1 t ADT: 9,500

I-55/I-74 NB

Fair

Over: WASH.ST/FAU 6360

0.4 MI S ILL RT 9, McLean, IL

Built 1962 Load: 79.4 t ADT: 21,550

I-55/I-74 SB

Fair

Over: WASH.ST/FAU 6360

0.4 MI S OF ILL RT 9, McLean, IL

Built 1962 Load: 79.4 t ADT: 21,550

I-55/74 (NB & SB)

Fair

Over: UNNAMED CREEK

1 MI N OF IL 9, McLean, IL

Built 1991 Load: 97.2 t ADT: 42,100

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

Related

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.