County profile · official public datasets

Clark County, IL

230 public highway bridges tracked in the FHWA National Bridge Inventory: 62.6% rated Good, 32.6% Fair, 4.8% Poor.

230
Public bridges
62.6%
Good condition
4.8%
Poor condition

The verdict

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

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

Top 15%
lowest Poor share in state
4.8%
Poor-condition share
230
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.

Clark County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Clark County ranks #15 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 4.8%). Clark County, Illinois contains 230 public highway bridges. Roughly 62.6% are rated “Good,” 32.6% “Fair,” and 4.8% “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

230

Public highway bridges in Clark County

Good condition

62.6%

144 of 230 rated 7-9

Fair condition

32.6%

75 of 230 rated 5-6

Poor condition

4.8%

11 of 230 rated 4 or below

In-state Poor-share rank

#15 of 102

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

Condition distribution

Share of 230 NBI-tracked bridges by lowest applicable component rating.

Good
62.6% (144)
Fair
32.6% (75)
Poor
4.8% (11)

Clark County's Poor-condition bridges carry 37,450 vehicle crossings a day

That is 8% of the county's reported daily bridge traffic on 4.8% of its bridges: Poor-condition structures carry more traffic than their share of the inventory. Each Poor bridge averages 3,405 crossings a day against 610 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 230 of 230 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

34.3% of Clark County's bridges have passed the 50-year mark

79 of the 230 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 62.6% 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 33.2% of the county's Poor-condition bridge traffic

I-70 (WB) over E LITTLE CREEK, built 1968, carries 12,450 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 11-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 37,450 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Clark County's bridges were built

230 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1980s, when 58 of the county's bridges still in the inventory were built, which is 25.2% 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 Clark County compares with Illinois's closest counties by inventory size

The 5 Illinois counties nearest Clark County in number of bridges, with their condition splits. Its 4.8% Poor share is the 2nd-lowest of these 6. Its average build year of 1978 against a peer-group mean of 1982 is in line with the group.

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

Bridge inventory size and condition shares for Clark County and the 5 Illinois counties closest to it in inventory size
County Bridges Poor
Morgan County 234 8.5%
Washington County 233 6%
Douglas County 232 1.3%
Clark County (this page) 230 4.8%
Jackson County 228 6.6%
McHenry County 227 20.3%

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

Similar inventory size

Nearest county inventories outside IL (230 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 230 Good 144 Fair 75 Poor 11

Fair-condition bridges (75)

CH 8(FAS 688)

Fair

Over: I-70

1.75 MI W IL 1, Clark, IL

Built 1968 Load: 38.6 t ADT: 2,150

OLD US 40

Fair

Over: KETTERING BRANCH

.23 MI W MARTINSVILL, Clark, IL

Built 1986 Load: 39.9 t ADT: 1,300

US 40(FAS 1707)

Fair

Over: TURKEY RUN CREEK

2.5 MI W MARTINSVILL, Clark, IL

Built 1955 Load: 41.8 t ADT: 2,750

ILL 1(FAP 332)

Fair

Over: BIG CREEK

2 MI N MARSHALL, Clark, IL

Built 1954 Load: 42.1 t ADT: 5,150

I-70 (WB)

Fair

Over: CROOKED CREEK

3.5 MI W OF STATE LN, Clark, IL

Built 1968 Load: 44.1 t ADT: 12,450

I-70 (EB)

Fair

Over: CROOKED CREEK

3.5 MI W STATE LINE, Clark, IL

Built 1968 Load: 44.1 t ADT: 12,450

FAP 832(IL 49)

Fair

Over: STREAM

6.5 MI S CASEY, Clark, IL

Built 1993 Load: 44.1 t ADT: 725

I-70 (EB)

Fair

Over: HAWKS CREEK

1 MI W STATE LINE, Clark, IL

Built 2002 Load: 44.1 t ADT: 14,000

I-70 (WB)

Fair

Over: HAWKS CREEK

1 MI W STATE LINE, Clark, IL

Built 2002 Load: 44.1 t ADT: 14,000

IL 49(FAP 832)

Fair

Over: TR1B TO LAMB BRANCH

.6 MI S OF WESTFIELD, Clark, IL

Built 1985 Load: 44.4 t ADT: 1,650

I-70 (WB)

Fair

Over: BIG CREEK

1 MI E ILL 1, Clark, IL

Built 1968 Load: 47.0 t ADT: 12,450

I-70 (EB)

Fair

Over: BIG CREEK

1 MI E ILL 1, Clark, IL

Built 1968 Load: 47.0 t ADT: 12,450

ILL 1 (FAP 332)

Fair

Over: MILL CREEK

N OF WEST UNION, Clark, IL

Built 2005 Load: 49.6 t ADT: 2,400

FAS 1658(CH26)

Fair

Over: MOUNTS BRANCH

1 MI SW MORIAH, Clark, IL

Built 1964 Load: 50.5 t ADT: 375

OLD US 40(SBI 11)

Fair

Over: TURKEY RUN CREEK

1.5 MI W MARTINSVILL, Clark, IL

Built 1986 Load: 51.5 t ADT: 1,000

I-70 (EB)

Fair

Over: IL 1(FAP 332)

N MARSHALL, Clark, IL

Built 1969 Load: 55.1 t ADT: 11,700

I-70 (WB)

Fair

Over: IL 1(FAP 332)

N MARSHALL, Clark, IL

Built 1969 Load: 55.1 t ADT: 12,450

I-70 (WB)

Fair

Over: MILL CREEK

W MARSHALL, Clark, IL

Built 1968 Load: 56.4 t ADT: 11,700

I-70

Fair

Over: E MILL CREEK

MP 144.3, Clark, IL

Built 1969 Load: 56.7 t ADT: 23,400

I-70

Fair

Over: TURKEY RUN CREEK

2.1 MI E IL 49 INT, Clark, IL

Built 1968 Load: 63.8 t ADT: 22,800

US 40 (FAS 1707)

Fair

Over: MILL CREEK

.5 MI E CLARK CTR, Clark, IL

Built 2011 Load: 75.2 t ADT: 2,750

I-70

Fair

Over: E MILL CREEK TRIB

MP 143.3, Clark, IL

Built 1969 Load: 89.1 t ADT: 23,400

US 40(FAS 1707)

Fair

Over: STREAM

W EDGE OF MARSHALL, Clark, IL

Built 1953 Load: 89.1 t ADT: 3,100

I-70

Fair

Over: E MILL CREEK

MP 144.2, Clark, IL

Built 1969 Load: 97.2 t ADT: 23,400

I-70

Fair

Over: KETTERING BRANCH

NE MARTINSVILLE, Clark, IL

Built 1968 Load: 97.2 t ADT: 23,400

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.