County profile · official public datasets

Union County, IL

192 public highway bridges tracked in the FHWA National Bridge Inventory: 54.7% rated Good, 41.7% Fair, 3.6% Poor.

192
Public bridges
54.7%
Good condition
3.6%
Poor condition

The verdict

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

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

Top 8%
lowest Poor share in state
3.6%
Poor-condition share
192
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.

Union County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Union County ranks #8 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 3.6%). Union County, Illinois contains 192 public highway bridges. Roughly 54.7% are rated “Good,” 41.7% “Fair,” and 3.6% “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

192

Public highway bridges in Union County

Good condition

54.7%

105 of 192 rated 7-9

Fair condition

41.7%

80 of 192 rated 5-6

Poor condition

3.6%

7 of 192 rated 4 or below

In-state Poor-share rank

#8 of 102

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

Condition distribution

Share of 192 NBI-tracked bridges by lowest applicable component rating.

Good
54.7% (105)
Fair
41.7% (80)
Poor
3.6% (7)

Union County's Poor-condition bridges carry 26,150 vehicle crossings a day

That is 8.6% of the county's reported daily bridge traffic on 3.7% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 3,736 crossings a day against 887 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 190 of 192 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

34.4% of Union County's bridges have passed the 50-year mark

66 of the 192 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 54.7% 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 27.9% of the county's Poor-condition bridge traffic

FAI 57 SB & US 51 over FAS 926-BIG CREEK, built 1959, carries 7,300 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 7-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 26,150 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Union County's bridges were built

192 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 39 of the county's bridges still in the inventory were built, which is 20.3% of those with a recorded year. That cohort is now 35 to 44 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 Union County compares with Illinois's closest counties by inventory size

The 5 Illinois counties nearest Union County in number of bridges, with their condition splits. Its 3.6% Poor share is the 1st-lowest of these 6. Its average build year of 1981 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 Union County and the 5 Illinois counties closest to it in inventory size
County Bridges Poor
Warren County 199 7.5%
Crawford County 197 6.1%
Jo Daviess County 193 9.8%
De Witt County 192 5.7%
Union County (this page) 192 3.6%
Clinton County 190 7.4%

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

Similar inventory size

Nearest county inventories outside IL (192 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 192 Good 105 Fair 80 Poor 7

All bridges (192)

HAPPY HOLLER RD

Good

Over: CROOKED CREEK

1 MILE SW OF DONGOLA, Union, IL

Built 2015 Load: 32.4 t ADT: 50

CLARK LN

Good

Over: TRIB TO DUTCH CREEK

1 MI SW OF JONESBORO, Union, IL

Built 2014 Load: 32.4 t ADT: 25

TR 51

Good

Over: SEMINARY FORK

1 MI S ALTO PASS, Union, IL

Built 2013 Load: 32.4 t ADT: 25

TR 239

Good

Over: PORTERFIELD CREEK

2 MI NE DONGOLA, Union, IL

Built 2013 Load: 32.4 t ADT: 50

KERR CANYON RD

Good

Over: BRADSHAW CREEK

0.1MI S OF TR 57, Union, IL

Built 2016 Load: 32.4 t ADT: 10

TR-152 (Hughey Lan

Good

Over: Trib. Cache River

3 MI SE OF COBDEN, Union, IL

Built 2017 Load: 32.4 t ADT: 25

FAS 926

Good

Over: TRIB TO LINGLE CREEK

0.8 MI E OF IL 127, Union, IL

Built 1988 Load: 32.4 t ADT: 325

TR 115

Good

Over: UNNAMED STREAM

TRAIL TEARS FOREST, Union, IL

Built 1988 Load: 32.4 t ADT: 25

TR 115A

Good

Over: UNNAMED CREEK

TRAIL OF TEARS ST PK, Union, IL

Built 1997 Load: 32.4 t ADT: 10

NURSERY ROAD

Good

Over: TRIB TO CLEAR CREEK

UNION CO ST NURSERY, Union, IL

Built 1993 Load: 32.4 t ADT: 25

OR 3 (OFF US 51)

Good

Over: STREAM

1 MI N OF ILL 146, Union, IL

Built 1968 Load: 33.0 t ADT: 1,700

FAS 926

Good

Over: PORTERFIELD CREEK

3.3 MI E DONGOLA, Union, IL

Built 1978 Load: 34.3 t ADT: 650

FAI 57 RAMP 219 ON

Good

Over: STREAM

0.2 MI E DONGOLA, Union, IL

Built 1959 Load: 36.0 t ADT: 175

UNION SPRINGS RD

Good

Over: CEDAR CREEK

1.4MI EAST ALTO PASS, Union, IL

Built 2018 Load: 36.6 t ADT: 50

FAS 926-CH 14

Good

Over: BIG CREEK

1 MI NE OF DONGOLA, Union, IL

Built 1991 Load: 36.9 t ADT: 1,000

NASH ROAD

Good

Over: TRIB TO BIG CREEK

WRIGHT LA JUNCTION, Union, IL

Built 2019 Load: 37.3 t ADT: 10

BAUER RD

Good

Over: DUTCH CREEK

0.7 MI N OF TR 217, Union, IL

Built 2019 Load: 38.6 t ADT: 50

JOHNSON DAIRY ROAD

Good

Over: ADDS BRANCH

3.2 MI EAST OF I-57, Union, IL

Built 2022 Load: 38.9 t ADT: 10

ILL 3

Good

Over: BIG MUDDY RIVER

AT JACKSON CO LINE, Union, IL

Built 1958 Load: 40.2 t ADT: 1,100

NASH ROAD

Good

Over: TRIB TO BIG CREEK

5 MI SE OF ANNA, Union, IL

Built 2020 Load: 40.2 t ADT: 10

I 57 NB

Good

Over: CH 17 CHRISTIAN CHAP

0.6 MI S ILL 146, Union, IL

Built 1959 Load: 41.1 t ADT: 6,600

I 57 SB

Good

Over: CH 17 CHRISTIAN CHAP

0.6 MI S ILL 146, Union, IL

Built 1959 Load: 41.1 t ADT: 6,600

MILLER ROAD

Good

Over: MILL CREEK TRIB

1.3 MI N MILL CREEK, Union, IL

Built 2022 Load: 41.1 t ADT: 10

ILL 127

Good

Over: DUTCH CREEK

1.5 MI SO JONESBORO, Union, IL

Built 1987 Load: 41.8 t ADT: 1,600

ILL RTE 127

Good

Over: MILL CREEK

0.5 MI N MILL CREEK, Union, IL

Built 1988 Load: 43.1 t ADT: 900

NEW US 51

Good

Over: LITTLE CREEK

2 MI NW OF FAS 2936, Union, IL

Built 1998 Load: 44.7 t ADT: 2,900

FAI 57 SB

Good

Over: ILL 146

OVER ILL 146, Union, IL

Built 1958 Load: 46.3 t ADT: 7,150

FAP 885-IL 127/146

Good

Over: GREEN CREEK

0.3 MI E IL 127, Union, IL

Built 2002 Load: 52.8 t ADT: 5,000

I-57

Good

Over: SHAKE RAG ROAD

E OF DONGOLA, Union, IL

Built 2020 Load: 53.1 t ADT: 6,900

I-57 SB

Good

Over: SHAKE RAG ROAD

E OF DONGOLA, Union, IL

Built 2019 Load: 53.1 t ADT: 6,900

I 57 NB

Good

Over: CYPRESS CREEK

0.7 MI S ILL 146, Union, IL

Built 1959 Load: 59.6 t ADT: 6,600

I 57 SB

Good

Over: CYPRESS CREEK

0.7 MI S ILL 146, Union, IL

Built 1959 Load: 59.6 t ADT: 6,600

FAS 924-CH 4 EXIT

Good

Over: INTERSTATE 57

0.2 MI W LICK CREEK, Union, IL

Built 1959 Load: 60.3 t ADT: 600

FAI 57 NB

Good

Over: ILL 146

OVER ILL 146, Union, IL

Built 1958 Load: 75.2 t ADT: 7,150

FAS 1911 (UNMARKED

Good

Over: DRURY CREEK

0.8 MI N COBDEN, Union, IL

Built 2016 Load: 95.3 t ADT: 1,150

CH 3

Poor

Over: LITTLE CREEK

CH 3 IN DONGOLA, Union, IL

Built 1935 Load: 13.6 t ADT: 600

FAS 924

Poor

Over: BRADSHAW CR

3 MI SW OF LICK CR, Union, IL

Built 1981 Load: 24.0 t ADT: 2,150

TR 295

Poor

Over: CROOKED CREEK

0.94 MI S OF CH 3, Union, IL

Built 1900 Load: 28.2 t ADT: 100

FAI 57 SB & US 51

Poor

Over: FAS 926-BIG CREEK

0.2 MI E DONGOLA, Union, IL

Built 1959 Load: 34.0 t ADT: 7,300

I 57 NB & US 51 NB

Poor

Over: FAS 926-BIG CREEK

0.2 MI E DONGOLA, Union, IL

Built 1959 Load: 34.0 t ADT: 7,300

ILL 146

Poor

Over: CLEAR CREEK

2 MI E. OF ILL 3, Union, IL

Built 1976 Load: 34.0 t ADT: 4,050

ILL 146

Poor

Over: CYPRESS CREEK

1 MI W IS 57, Union, IL

Built 1931 Load: 36.9 t ADT: 4,650

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

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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.