County profile · official public datasets

LaSalle County, IL

528 public highway bridges tracked in the FHWA National Bridge Inventory: 39.4% rated Good, 48.3% Fair, 12.3% Poor.

528
Public bridges
39.4%
Good condition
12.3%
Poor condition

The verdict

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

LaSalle County posts a higher-than-median Poor-condition share among rated counties in the state across large county bridge inventory.

84th
of 102 on Poor share
12.3%
Poor-condition share
528
public highway bridges
1978
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.

LaSalle County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, LaSalle County ranks #84 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 12.3%). LaSalle County, Illinois contains 528 public highway bridges. Roughly 39.4% are rated “Good,” 48.3% “Fair,” and 12.3% “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

528

Public highway bridges in LaSalle County

Good condition

39.4%

208 of 528 rated 7-9

Fair condition

48.3%

255 of 528 rated 5-6

Poor condition

12.3%

65 of 528 rated 4 or below

In-state Poor-share rank

#84 of 102

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

Condition distribution

Share of 528 NBI-tracked bridges by lowest applicable component rating.

Good
39.4% (208)
Fair
48.3% (255)
Poor
12.3% (65)

LaSalle County's Poor-condition bridges carry 81,630 vehicle crossings a day

That is 7.5% of the county's reported daily bridge traffic on 12.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,275 crossings a day against 2,002 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 525 of 528 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

39% of LaSalle County's bridges have passed the 50-year mark

206 of the 528 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 39.4% 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 13.1% of the county's Poor-condition bridge traffic

US 6 FAP 623 over FOX RIVER, built 1928, carries 10,700 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 65-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 81,630 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When LaSalle County's bridges were built

528 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 112 of the county's bridges still in the inventory were built, which is 21.2% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1978) matches the Illinois average (1979).

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

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

The 5 Illinois counties nearest LaSalle County in number of bridges, with their condition splits. Its 12.3% Poor share is the 5th-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1979 is in line with the group.

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

Bridge inventory size and condition shares for LaSalle County and the 5 Illinois counties closest to it in inventory size
County Bridges Poor
Livingston County 579 8.3%
Iroquois County 570 14.4%
LaSalle County (this page) 528 12.3%
Madison County 523 8.4%
Vermilion County 494 7.3%
St. Clair County 486 9.1%

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 LaSalle 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 LaSalle County, both outside Illinois so the neighborhoods are not the same-state size table above.

Similar inventory size

Nearest county inventories outside IL (528 bridges here).

Similar average build year

Nearest mean year-built outside IL (1978 here).

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

All 528 Good 208 Fair 255 Poor 65

Good-condition bridges (208)

FAI-80 WB

Good

Over: E 3rd Road (MS 6100A)

1.1 MI E JCT IL 251, LaSalle, IL

Built 1961 Load: 22.7 t ADT: 12,800

TR 454 A

Good

Over: Trib Waupecan Creek

E 28th N 1772, LaSalle, IL

Built 1930 Load: 24.3 t ADT: 20

TR 137

Good

Over: Spring Creek

0.5 Mi W. of US 52, LaSalle, IL

Built 1930 Load: 24.3 t ADT: 150

TR-48

Good

Over: BAILEY CREEK

E 3RD N 1840, LaSalle, IL

Built 1968 Load: 25.3 t ADT: 150

FAI-80 EB

Good

Over: E 3rd Road (MS 6100A)

1.1 MI E JCT IL 251, LaSalle, IL

Built 1961 Load: 25.6 t ADT: 12,800

TR-49

Good

Over: L. VERMILLION CR.

N 45TH E 480, LaSalle, IL

Built 1953 Load: 25.9 t ADT: 100

US 52 FAP 607

Good

Over: INDIAN CREEK

2.12 MI E OF ILL 23, LaSalle, IL

Built 1988 Load: 29.2 t ADT: 1,500

US 52

Good

Over: BUCK CREEK

12.22 MI E OF IL 251, LaSalle, IL

Built 1997 Load: 29.5 t ADT: 1,200

FAS268 B/CH15

Good

Over: PERSON CREEK

E 22ND N 2600, LaSalle, IL

Built 1955 Load: 29.5 t ADT: 900

FAS 268 A

Good

Over: ILL RIV & OR 11

.41 M S OF US 6, LaSalle, IL

Built 1999 Load: 31.1 t ADT: 3,450

TOW PATH ROAD

Good

Over: CLARKS RUN

0.6 MI. E ILL 178, LaSalle, IL

Built 1967 Load: 31.8 t ADT: 25

TR 310

Good

Over: BR COVEL CREEK

E 18TH N 2330, LaSalle, IL

Built 1930 Load: 32.1 t ADT: 100

IL 23 SB IN STREAT

Good

Over: PRAIRIE CREEK

14.30 MI S OF ILL 71, LaSalle, IL

Built 1965 Load: 32.4 t ADT: 7,700

IL 71

Good

Over: INTER STREAM

.27 MILE N US 6, LaSalle, IL

Built 1999 Load: 32.4 t ADT: 7,400

IL 178 FAS 1279

Good

Over: CLARK RUN

0.92 MI S OF US 6, LaSalle, IL

Built 2007 Load: 32.4 t ADT: 3,550

I-80 EB & WB

Good

Over: CLARK RUN CREEK

1.8 MI E JC I 80 178, LaSalle, IL

Built 2004 Load: 32.4 t ADT: 29,300

FAS 174/CH 9

Good

Over: I-80 /Test Rd Access

4.0 M E of IL 178, LaSalle, IL

Built 2021 Load: 32.4 t ADT: 150

IL 178 FAS 1279

Good

Over: CREEK

2.25 MI S OF IL 71, LaSalle, IL

Built 2007 Load: 32.4 t ADT: 2,750

IL 178 FAS 1279

Good

Over: STREAM

0.60 MI S OF IL 71, LaSalle, IL

Built 2007 Load: 32.4 t ADT: 2,750

IL 71 FAP 311

Good

Over: INTERM. STREAM

2.57 MI N OF I-80, LaSalle, IL

Built 2008 Load: 32.4 t ADT: 5,600

IL 17 FAP 649

Good

Over: S BR MOON CREEK

0.8 MI E/OLD IL 179, LaSalle, IL

Built 2009 Load: 32.4 t ADT: 900

IL 71/FAP 619

Good

Over: UNNAMED TRIB.VERM RV

0.40 MI NE IL 251, LaSalle, IL

Built 2011 Load: 32.4 t ADT: 1,300

US 6 / FAP 623

Good

Over: creek

1.91 mi W of IL 170, LaSalle, IL

Built 2013 Load: 32.4 t ADT: 2,850

IL 170 FAP 786

Good

Over: Hog Run

5.93 mi S of US 6, LaSalle, IL

Built 2014 Load: 32.4 t ADT: 1,200

IL 170 FAP 786

Good

Over: Unnamed Creek

6.98 mi S of US 6, LaSalle, IL

Built 2014 Load: 32.4 t ADT: 1,200

CO HWY 43

Good

Over: PECUMSAGANCREEK

3 MI N OF UTICA ILL, LaSalle, IL

Built 1979 Load: 32.4 t ADT: 950

TR 270 E 1525TH

Good

Over: INDIAN CREEK

E 1525 N 4750, LaSalle, IL

Built 1979 Load: 32.4 t ADT: 125

CH 43 E 8TH RD

Good

Over: TOMAHAWK CREEK

E 8TH N3690, LaSalle, IL

Built 1980 Load: 32.4 t ADT: 900

TR 52 E 3RD

Good

Over: LITTLE VERMILION

E 3RD N 4100, LaSalle, IL

Built 1980 Load: 32.4 t ADT: 825

TR 160 E 9TH

Good

Over: SUTPHENS RUN

E 9TH N 4615, LaSalle, IL

Built 1980 Load: 32.4 t ADT: 25

TR 571

Good

Over: STREAM

N 1ST E 1050, LaSalle, IL

Built 1982 Load: 32.4 t ADT: 50

TR 284 E 16TH

Good

Over: BUCK CREEK

E16TH N 3450TH, LaSalle, IL

Built 1983 Load: 32.4 t ADT: 200

TR 198 E 11TH

Good

Over: STREAM

E11TH N3075TH, LaSalle, IL

Built 1983 Load: 32.4 t ADT: 50

TR 230

Good

Over: CREEK

E 13TH RD N 3550, LaSalle, IL

Built 1984 Load: 32.4 t ADT: 25

TR 322 B

Good

Over: COAL RUN

E 19th N 1250, LaSalle, IL

Built 1984 Load: 32.4 t ADT: 450

TR 166

Good

Over: CREEK

E 10TH RD N 750, LaSalle, IL

Built 1984 Load: 32.4 t ADT: 25

TR 523A

Good

Over: OTTER CREEK

N 15TH RD E 2370, LaSalle, IL

Built 1985 Load: 32.4 t ADT: 200

TR 170

Good

Over: PECUMSAGAM CREEK

E 10TH RD N 3270, LaSalle, IL

Built 1985 Load: 32.4 t ADT: 50

TR 222

Good

Over: BR INDIAN CREEK

E 1250 TH N 4605, LaSalle, IL

Built 1986 Load: 32.4 t ADT: 250

TR 148

Good

Over: LITTLE VERMILION

E 8TH RD N 4192, LaSalle, IL

Built 1986 Load: 32.4 t ADT: 75

TR 493

Good

Over: WOLF CR

N 18 TH E 1980, LaSalle, IL

Built 1986 Load: 32.4 t ADT: 50

FAS 263 CH 44

Good

Over: CREEK

E 950 TH N 1425, LaSalle, IL

Built 1987 Load: 32.4 t ADT: 250

TR 471

Good

Over: BR BAILEY CR

N 1950 TH E 550, LaSalle, IL

Built 1987 Load: 32.4 t ADT: 100

TR441

Good

Over: BR. COVEL CREEK

N22ND E2010TH, LaSalle, IL

Built 1987 Load: 32.4 t ADT: 25

TR 462

Good

Over: ROODS CREEK

E2975TH N4100, LaSalle, IL

Built 1987 Load: 32.4 t ADT: 25

TR 122 B

Good

Over: SANDY CR.

E 7TH RD N 975, LaSalle, IL

Built 1987 Load: 32.4 t ADT: 50

TR 125B

Good

Over: L VERMILLION RIVER

N 40TH RD E 625TH, LaSalle, IL

Built 1989 Load: 32.4 t ADT: 25

TR 561

Good

Over: DRAINAGE DITCH

N6TH RD E 815, LaSalle, IL

Built 1988 Load: 32.4 t ADT: 10

FAS 261 CH 34

Good

Over: CREEK

N 27TH RD E 1350, LaSalle, IL

Built 1989 Load: 32.4 t ADT: 1,200

TR 483

Good

Over: BAILEY CREEK

N1851ST E325TH, LaSalle, IL

Built 1989 Load: 32.4 t ADT: 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.