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)

CH 6 N21ST RD

Good

Over: COVEL CREEK

N 21ST E 1920, LaSalle, IL

Built 2015 Load: 32.4 t ADT: 1,100

CH 51

Good

Over: Walbridge Creek

1.5 Mi W of CH 15, LaSalle, IL

Built 2013 Load: 32.4 t ADT: 1,300

TR-187

Good

Over: Spring Creek

N. 37th E. 120, LaSalle, IL

Built 2016 Load: 32.4 t ADT: 200

TR 322

Good

Over: COVEL CREEK

E 19TH N 2095, LaSalle, IL

Built 2016 Load: 32.4 t ADT: 50

TR 152A

Good

Over: CREEK

E 9TH N 6TH, LaSalle, IL

Built 1988 Load: 32.4 t ADT: 50

FAS268 A/CH 15

Good

Over: MILL RACE

CH 15/S MILL RACE, LaSalle, IL

Built 1937 Load: 32.4 t ADT: 3,450

FAS1277/COMMERCIAL

Good

Over: LONG CREEK

COMMERCIAL ST W/MAIN, LaSalle, IL

Built 1997 Load: 32.4 t ADT: 1,550

10TH AVE & 4TH ST

Good

Over: MENDOTA CREEK

10TH AVE & 4TH ST, LaSalle, IL

Built 2001 Load: 32.4 t ADT: 50

3RD ST

Good

Over: MENDOTA CR

S EDGE MENDOTA, LaSalle, IL

Built 2006 Load: 32.4 t ADT: 375

LINCOLN EAST/MS222

Good

Over: CLARK RUN (WEST)

EAST OF IL 178, LaSalle, IL

Built 2011 Load: 32.4 t ADT: 425

POST ST

Good

Over: GOOSE CREEK

150 FT E OF IL 23, LaSalle, IL

Built 1994 Load: 32.4 t ADT: 700

WASSON STREET

Good

Over: PRAIRIE CREEK

W OF BRONSON STR, LaSalle, IL

Built 1985 Load: 32.4 t ADT: 775

Otter Creek

Good

Over: N trib. of Coal Run

2 300 S. of RT.18, LaSalle, IL

Built 2012 Load: 32.4 t ADT: 1,500

VERMILION ST.

Good

Over: COAL RUN CREEK

S SPRING-N BROMBACH, LaSalle, IL

Built 1995 Load: 32.4 t ADT: 500

BROADWAY ST.

Good

Over: BNSF RR & IL STREET

0.3 MI.E.OF ILL 23, LaSalle, IL

Built 2008 Load: 32.4 t ADT: 2,000

DIVISION ST

Good

Over: PRAIRIE CREEK

1/2 BLK E OF WALNUT, LaSalle, IL

Built 2012 Load: 32.4 t ADT: 425

BAZORE ST (FAU 614

Good

Over: PRAIRIE CREEK

1/2 BLK E OF WALNUT, LaSalle, IL

Built 2013 Load: 32.4 t ADT: 3,300

Remington Rd

Good

Over: Otter Creek

1/8 Mi N Marilla Rd, LaSalle, IL

Built 2014 Load: 32.4 t ADT: 300

OAK ST IN TONICA

Good

Over: BAILEY CREEK

OAK ST OV BAILEY CR, LaSalle, IL

Built 1990 Load: 32.4 t ADT: 50

STARVED RCK LODGE

Good

Over: FOX CANYON

N 2675-E880, LaSalle, IL

Built 1994 Load: 32.4 t ADT: 500

TR 310

Good

Over: OTTER CREEK

E 18TH N 1500, LaSalle, IL

Built 1921 Load: 32.7 t ADT: 400

TR 107

Good

Over: VERMILION CREEK

N 42ND E 815, LaSalle, IL

Built 1974 Load: 34.0 t ADT: 100

TR 523A

Good

Over: OTTER CREEK

N 15TH E 2190, LaSalle, IL

Built 1933 Load: 34.3 t ADT: 250

CH. 23

Good

Over: Vermillion River

E 651 N 2525, LaSalle, IL

Built 2017 Load: 35.0 t ADT: 900

TR 19

Good

Over: INDIAN CREEK

N 47TH E 1360, LaSalle, IL

Built 1930 Load: 35.3 t ADT: 100

TR 332 A

Good

Over: OTTER CREEK

E 20TH N 1510, LaSalle, IL

Built 1930 Load: 35.3 t ADT: 50

TR 503

Good

Over: OTTER CREEK

N 16TH E 2430, LaSalle, IL

Built 1935 Load: 35.3 t ADT: 1,700

ILL 23/IL 71 FAP 6

Good

Over: ILL MICH CANAL

LASALLE ST IN OTTAWA, LaSalle, IL

Built 1999 Load: 35.6 t ADT: 10,400

ILL 23 & 71

Good

Over: ILL MICH CANAL

COLUMBUS ST OTTAWA, LaSalle, IL

Built 1999 Load: 35.6 t ADT: 10,800

IL 179

Good

Over: LONG POINT CREEK

2.8 M E OF US 51, LaSalle, IL

Built 1995 Load: 36.3 t ADT: 300

CH 45

Good

Over: DIAMOND CREEK

E 11TH RD N 120, LaSalle, IL

Built 1986 Load: 36.3 t ADT: 225

CO RD 5

Good

Over: WOLF CREEK

N 17TH E 1925, LaSalle, IL

Built 2020 Load: 36.3 t ADT: 1,150

I-80 WB

Good

Over: FAU 6081 LASALLE RD

.8 MI E OF IL 251JCT, LaSalle, IL

Built 1996 Load: 37.3 t ADT: 12,800

ILL 251

Good

Over: BAILEY CREEK

3.63 MI S OF ILL 71, LaSalle, IL

Built 1999 Load: 37.3 t ADT: 1,700

TR 561

Good

Over: BR.PRAIRIE CR.

N 6TH E 1060, LaSalle, IL

Built 1936 Load: 37.3 t ADT: 25

TR 108

Good

Over: TOMAHAWK CREEK

E 6TH RD N 3510, LaSalle, IL

Built 1987 Load: 37.6 t ADT: 175

ILL 179

Good

Over: MOON CREEK

0.16 MI S OF ILL 17, LaSalle, IL

Built 1984 Load: 37.9 t ADT: 300

FAS 174N/CH 41

Good

Over: BRANCH INDIAN CREEK

E1351 N4742, LaSalle, IL

Built 2002 Load: 37.9 t ADT: 200

ILL 251

Good

Over: BAILEY CREEK

4.0 MI S OF ILL 71, LaSalle, IL

Built 1999 Load: 38.2 t ADT: 1,700

TR 48A

Good

Over: DRAINAGE DITCH

E. 3RD RD N. 1450, LaSalle, IL

Built 1992 Load: 38.2 t ADT: 50

IL 17 FAP 649

Good

Over: SANDY CREEK

2MI E OF WENNONA, LaSalle, IL

Built 1995 Load: 38.6 t ADT: 900

US 52

Good

Over: TOMAHAWK CREEK

6.98 MI E OF ILL 251, LaSalle, IL

Built 1997 Load: 38.6 t ADT: 1,400

MS 7430(LONE TREE

Good

Over: I 80

1 MI E OF IL 178, LaSalle, IL

Built 1997 Load: 38.9 t ADT: 100

IL 71

Good

Over: INTERMIT STREAM

5.90 MI E OF IL 178, LaSalle, IL

Built 2007 Load: 38.9 t ADT: 1,700

TR 314

Good

Over: BUCK CREEK

E 18 N 3450, LaSalle, IL

Built 1998 Load: 38.9 t ADT: 675

FAS 1267/TERRA COT

Good

Over: I 80

7.0 M E OF IL 178, LaSalle, IL

Built 1997 Load: 39.2 t

TR 101

Good

Over: ROODS CREEK

N4201 E.2710, LaSalle, IL

Built 1992 Load: 39.2 t ADT: 300

SHERIDAN ROAD

Good

Over: MISSION CREEK

0.7 MI N OF US 52, LaSalle, IL

Built 1930 Load: 39.5 t ADT: 1,700

FAS 1274

Good

Over: SOMONAUK CREEK

N 48TH E 2725, LaSalle, IL

Built 1966 Load: 39.5 t ADT: 3,100

1ST STREET

Good

Over: MENDOTA CREEK

100FT W OF ORCHARD, LaSalle, IL

Built 1997 Load: 39.9 t ADT: 225

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.