County profile · official public datasets

McDonough County, IL

209 public highway bridges tracked in the FHWA National Bridge Inventory: 53.6% rated Good, 39.7% Fair, 6.7% Poor.

Compiled by PlainBridges

209
Public bridges: 53.6%
Good condition: 6.7%
Poor condition

The verdict

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

McDonough County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.

Top 38%
lowest Poor share in state: 6.7%
Poor-condition share: 209
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.

McDonough County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, McDonough County ranks #39 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.7%). McDonough County, Illinois contains 209 public highway bridges. Roughly 53.6% are rated “Good,” 39.7% “Fair,” and 6.7% “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

209

Public highway bridges in McDonough County

Good condition

53.6%

112 of 209 rated 7-9

Fair condition

39.7%

83 of 209 rated 5-6

Poor condition

6.7%

14 of 209 rated 4 or below

In-state Poor-share rank

#39 of 102

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

Condition distribution

Share of 209 NBI-tracked bridges by lowest applicable component rating.

Good

53.6% (112)

Fair

39.7% (83)

Poor

6.7% (14)

McDonough County's Poor-condition bridges carry 4,270 vehicle crossings a day

That is 2.9% of the county's reported daily bridge traffic on 6.7% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 305 crossings a day against 229 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 209 of 209 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

25.8% of McDonough County's bridges have passed the 50-year mark

54 of the 209 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 53.6% 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 43.3% of the county's Poor-condition bridge traffic

ILL 9 over DROWNING FORK, built 1960, carries 1,850 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 14-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 4,270 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

1
1900s

8
1910s

2
1920s

5
1930s

10
1940s

4
1950s

17
1960s

6
1970s

13
1980s

41
1990s

46
2000s

26
2010s

27
2020s

3

What this shows Construction peaked in the 1990s, when 46 of the county's bridges still in the inventory were built, which is 22% of those with a recorded year. That cohort is now 25 to 34 years old in the 2024 inventory. Its average build year (1981) matches the Illinois average (1979).

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

The 5 Illinois counties nearest McDonough County in number of bridges, with their condition splits. Its 6.7% Poor share is the 4th-lowest of these 6. Its average build year of 1981 against a peer-group mean of 1983 is in line with the group.

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

Bridge inventory size and condition shares for McDonough County and the 5 Illinois counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
White County	214	29.4%	64%	6.5%	1986
Fulton County	210	22.9%	56.2%	21%	1977
McDonough County (this page)	209	53.6%	39.7%	6.7%	1981
Williamson County	201	67.2%	29.4%	3.5%	1985
Warren County	199	69.3%	23.1%	7.5%	1985
Crawford County	197	33%	60.9%	6.1%	1983

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

Similar inventory size

Nearest county inventories outside IL (209 bridges here).

Grant County, LA · 209 bridges
Clinton County, OH · 209 bridges
Iowa County, WI · 209 bridges
Clinton County, IN · 210 bridges

Similar average build year

Nearest mean year-built outside IL (1981 here).

Franklin County, OH · avg 1981 · 922 bridges
Greenville County, SC · avg 1981 · 635 bridges
Montgomery County, OH · avg 1981 · 632 bridges
Shawnee County, KS · avg 1981 · 563 bridges

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

All 209 Good 112 Fair 83 Poor 14

All bridges (209)

Sort:

McDonough County Bridge Snapshot

Condition distribution

McDonough County's Poor-condition bridges carry 4,270 vehicle crossings a day

25.8% of McDonough County's bridges have passed the 50-year mark

One structure carries 43.3% of the county's Poor-condition bridge traffic

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

Nationwide counties with similar inventory size or average build year

Similar inventory size

Similar average build year

All bridges (209)

TR 396

TR 249

TR 440

TR 271

TR 286-CANDY LANE

TR 340

TR 248

TR 248

TR 270

TR 196

TR 150

TR 52

TR 311

TR 301

TR 237

POLLOCK RD-TR 58

TR 150-BECK RD

TR 415

TR 58

TR 284

TR 379

TR 362

TR 342

TR 354

TR 459

TR 419

TR 459

FAU 6923

CH 17

US 67

TR-117

FAS 435-CH 24

TR 55

TR 100A

HEFFNER RD-TR 298

ILL 9

IL 336

TOWNSHIP RD 950E

TR 456A

IL 336

SPRING LAKE RD/CH

IL 336

FAS 441 - CH 9

LAKE ARGYLE PARK

CH 5

TR 225

TR 15

TR 234

CH-26 (FAS-441)

TR 477

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