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)

ILL RTE 127

Fair

Over: DUTCH CREEK

2.4 MI SO. JONESBORO, Union, IL

Built 1984 Load: 32.7 t ADT: 1,200

CH 3

Fair

Over: MILL CREEK

0.14M.E OF ILL 127, Union, IL

Built 1972 Load: 33.0 t ADT: 250

FAS 2936 (UNMARKED

Fair

Over: BR. BIGCREEK

DONGOLA, Union, IL

Built 1986 Load: 36.0 t ADT: 1,700

CH 11

Fair

Over: CYPRESS CREEK

3.3 MI S IL 146, Union, IL

Built 1989 Load: 36.0 t ADT: 50

ILL 127 & ILL 146

Fair

Over: GREEN CR TRIB

0.2 MI E ILL 127, Union, IL

Built 2004 Load: 36.9 t ADT: 5,000

ILL 3 & ILL 146

Fair

Over: RUNNING LAKE DITCH

2 MI S WARE, Union, IL

Built 1992 Load: 37.9 t ADT: 4,150

I 57 NB

Fair

Over: CACHE RIVER

2.1 MI N ILL 146, Union, IL

Built 1959 Load: 40.2 t ADT: 7,150

I 57 SB

Fair

Over: CACHE RIVER

2.1 MI N ILL 146, Union, IL

Built 1959 Load: 40.2 t ADT: 7,150

I 57 NB

Fair

Over: BRADSHAW CREEK

3.6 MI N ILL 146, Union, IL

Built 1959 Load: 41.1 t ADT: 7,150

I 57 SB

Fair

Over: BRADSHAW CREEK

3.6 MI N ILL 146, Union, IL

Built 1959 Load: 41.1 t ADT: 7,150

ILL 127

Fair

Over: LINGLE CREEK

0.3 MI N MILL CREEK, Union, IL

Built 1985 Load: 41.8 t ADT: 900

ILL 3 & ILL 146

Fair

Over: DRAINAGE DITCH

2.3 MI S OF ILL 146, Union, IL

Built 2005 Load: 42.1 t ADT: 4,150

ILL 146 & I-57

Fair

Over: STREAM

FAI 57-ILL 146, Union, IL

Built 1960 Load: 43.4 t ADT: 6,600

CH 3

Fair

Over: CROOKED CREEK

2.1M.W.DONGOLA CL., Union, IL

Built 1972 Load: 44.4 t ADT: 250

FAS 1911-OLD US 51

Fair

Over: CNIC RR

COBDEN, Union, IL

Built 1997 Load: 44.7 t ADT: 3,050

I-57 NB

Fair

Over: BIG CREEK

2 MI N DONGOLA, Union, IL

Built 2021 Load: 45.4 t ADT: 6,600

ILL 3

Fair

Over: RUNNING LAKE DITCH

2.1 MI S JACKSON CO, Union, IL

Built 1932 Load: 47.3 t ADT: 1,100

I-57 SB

Fair

Over: BIG CREEK

2 MI N DONGOLA, Union, IL

Built 2020 Load: 50.9 t ADT: 6,600

ILL 146

Fair

Over: DUTCH CREEK

4 MI W. JONESBORO, Union, IL

Built 1974 Load: 52.5 t ADT: 4,050

I 57 NB

Fair

Over: TR 276 N LICK CR RD

1.5 MI S JOHNSON CO, Union, IL

Built 1959 Load: 53.1 t ADT: 7,950

I 57 SB

Fair

Over: TR 276 N LICK CR RD

1.5 MI S JOHNSON CO, Union, IL

Built 1959 Load: 53.1 t ADT: 7,950

US 51

Fair

Over: CACHE CREEK

2 MI N ANNA, Union, IL

Built 1964 Load: 54.4 t ADT: 5,950

US 51 NB

Fair

Over: FAI 57 SB

0.5 MI N DONGOLA, Union, IL

Built 1959 Load: 55.1 t

ILL 146

Fair

Over: TRIB.OF CACHE CREEK

2 MI W.JOHNSON CO., Union, IL

Built 1932 Load: 55.7 t ADT: 2,500

US 51-FAP 322

Fair

Over: DRURY CR-CNIC RR

2.7 MI S JACKSON CO, Union, IL

Built 2005 Load: 61.9 t ADT: 5,500

US RTE 51

Fair

Over: CREEK

2.0 MI S JACKSON CO, Union, IL

Built 1968 Load: 89.1 t ADT: 5,500

I 57

Fair

Over: N.FORK LICK CREEK

1.7 MI S JOHNSON CO., Union, IL

Built 1960 Load: 89.1 t ADT: 15,900

TR 261

Fair

Over: CLEAR CR TRIB

3.25 MI E IL3-146, Union, IL

Built 1988 Load: 89.1 t ADT: 175

TR 126B OFF US 51

Fair

Over: CREEK

0.7 MI N OF ILL 146, Union, IL

Built 1964 Load: 89.1 t ADT: 200

US 51

Fair

Over: STREAM

1.6 MI N OF IL 146, Union, IL

Built 1964 Load: 97.2 t ADT: 5,950

TR 134

Good

Over: STREAM

1 MI NE COBDEN, Union, IL

Built 1900 Load: 13.9 t ADT: 100

TR 231A

Good

Over: UNNAMED CREEK

.5 MI SE BALCON, Union, IL

Built 1975 Load: 15.2 t ADT: 25

FAS 926

Good

Over: BIG CREEK TRIB

CH14 IN DONGOLA, Union, IL

Built 1953 Load: 18.8 t ADT: 950

TR 99

Good

Over: BRADSHAW CREEK

2 MI W FAS1926, Union, IL

Built 1977 Load: 19.4 t ADT: 25

CH 7

Good

Over: BRADSHAW CREEK

1.4M.N. MT.PLEASANT, Union, IL

Built 1960 Load: 24.9 t ADT: 225

CH 7

Good

Over: CACHE RIVER

1M.N.MT.PLEASANT, Union, IL

Built 1960 Load: 27.9 t ADT: 225

FAS 0923

Good

Over: CANY CREEK

.8 M W ILL 127, Union, IL

Built 1965 Load: 27.9 t ADT: 400

FAS 0923

Good

Over: CLEAR CREEK

3.6M SE OF WOLF LAKE, Union, IL

Built 1959 Load: 28.2 t ADT: 400

TR 212

Good

Over: CYPRESS CK

2.5 MI E I-57, Union, IL

Built 1973 Load: 29.5 t ADT: 100

ILL 127

Good

Over: CLEAR CREEK

3 MI SO OF ALTO PASS, Union, IL

Built 1989 Load: 30.1 t ADT: 1,350

FAS 1926

Good

Over: CACHE RIVER TRIB

3.5M.E.COBDEN CL, Union, IL

Built 1968 Load: 30.8 t ADT: 600

FAS 926

Good

Over: CYPRESS CREEK

1.6 MI W.JOHNSON CO., Union, IL

Built 1978 Load: 30.8 t ADT: 500

FAS 923

Good

Over: UNNAMED STREAM

W EDGE UNIONCO FORST, Union, IL

Built 1970 Load: 31.8 t ADT: 400

ILL 127

Good

Over: MILL CREEK

1.4 MI N MILL CREEK, Union, IL

Built 1985 Load: 32.4 t ADT: 900

ILL 127

Good

Over: MILL CR

2.4 MI N MILL CREEK, Union, IL

Built 1986 Load: 32.4 t ADT: 900

TR 79A

Good

Over: CLEAR CREEK TRIB

0.9 MI.E OF ILL 127, Union, IL

Built 1977 Load: 32.4 t ADT: 175

TR 174

Good

Over: CREEK

1.3M.N.JCT.FAS 1926, Union, IL

Built 1978 Load: 32.4 t ADT: 10

TR 131

Good

Over: CLEAR CREEK

2.0 MI NE OF WARE, Union, IL

Built 1978 Load: 32.4 t ADT: 175

TR 57

Good

Over: DRURY CREEK

0.05 MI E OF CH 1, Union, IL

Built 1978 Load: 32.4 t ADT: 225

FAS 924

Good

Over: CACHE RIVER TRIB

5.2 MI E OF ANNA, Union, IL

Built 1981 Load: 32.4 t ADT: 2,150

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.