County profile · official public datasets

Macoupin County, IL

242 public highway bridges tracked in the FHWA National Bridge Inventory: 36.4% rated Good, 45.9% Fair, 17.8% Poor.

242
Public bridges: 36.4%
Good condition: 17.8%
Poor condition

The verdict

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

Macoupin County pairs a higher-than-median Poor-condition share among rated counties in the state with an older average build year than the state inventory.

95th
of 102 on Poor share: 17.8%
Poor-condition share: 242
public highway bridges: 1965
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.

Macoupin County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Macoupin County ranks #95 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 17.8%). Macoupin County, Illinois contains 242 public highway bridges. Roughly 36.4% are rated “Good,” 45.9% “Fair,” and 17.8% “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

242

Public highway bridges in Macoupin County

Good condition

36.4%

88 of 242 rated 7-9

Fair condition

45.9%

111 of 242 rated 5-6

Poor condition

17.8%

43 of 242 rated 4 or below

In-state Poor-share rank

#95 of 102

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

Condition distribution

Share of 242 NBI-tracked bridges by lowest applicable component rating.

Good

36.4% (88)

Fair

45.9% (111)

Poor

17.8% (43)

Macoupin County's Poor-condition bridges carry 16,655 vehicle crossings a day

That is 8.9% of the county's reported daily bridge traffic on 17.8% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 387 crossings a day against 497 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 242 of 242 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

48.8% of Macoupin County's bridges have passed the 50-year mark

118 of the 242 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 36.4% 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 25.2% of the county's Poor-condition bridge traffic

IL 111 over PIASA CREEK, built 1929, carries 4,200 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 43-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 16,655 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

pre-1900

1
1900s

32
1910s

8
1920s

11
1930s

23
1940s

1
1950s

15
1960s

15
1970s

23
1980s

34
1990s

26
2000s

30
2010s

16
2020s

7

What this shows Construction peaked in the 1980s, when 34 of the county's bridges still in the inventory were built, which is 14% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1965, 14 years older than the Illinois average of 1979.

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

The 5 Illinois counties nearest Macoupin County in number of bridges, with their condition splits. Its 17.8% Poor share is the 6th-lowest of these 6. Its average build year of 1965 against a peer-group mean of 1979 is 14 years older.

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

Bridge inventory size and condition shares for Macoupin County and the 5 Illinois counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Lake County	251	37.1%	53%	10%	1976
Piatt County	246	62.2%	31.7%	6.1%	1979
Macoupin County (this page)	242	36.4%	45.9%	17.8%	1965
Morgan County	234	48.7%	42.7%	8.5%	1984
Washington County	233	50.6%	43.3%	6%	1973
Douglas County	232	76.3%	22.4%	1.3%	1982

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

Similar inventory size

Nearest county inventories outside IL (242 bridges here).

Glenn County, CA · 242 bridges
Wabaunsee County, KS · 242 bridges
Tuscola County, MI · 242 bridges
Kings County, NY · 242 bridges

Similar average build year

Nearest mean year-built outside IL (1965 here).

Windsor County, VT · avg 1965 · 483 bridges
Bedford County, PA · avg 1965 · 417 bridges
Crawford County, PA · avg 1965 · 399 bridges
Harper County, KS · avg 1965 · 372 bridges

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

All 242 Good 88 Fair 111 Poor 43

All bridges (242)

Sort:

Macoupin County Bridge Snapshot

Condition distribution

Macoupin County's Poor-condition bridges carry 16,655 vehicle crossings a day

48.8% of Macoupin County's bridges have passed the 50-year mark

One structure carries 25.2% of the county's Poor-condition bridge traffic

How Macoupin 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 (242)

TR328

CH 23

TR 195

TR 132A

TR 186

TR 201

TR 233

TR 471

TR 477C

TR 480

TR 483A

TR-494

EMERSON AIRLINE RD

TR 109

ILL 138

TR 473

IL 111

ILL 16

TR 483

TR 113

TR 457

TR 251

SHIPMANN BLACKTOP

TR 325

TR 173

NILWOOD WAGGONER R

TOWNSHIP ROAD 227

BUNKER-HILCARLNVL-

ILL 138

STUNTN BUNKR HIL R

ILL 108

TR 83

TR 514 / DICKEY RO

TOWNSHIP ROAD 473

IL 108

SHIPMAN BLACKTOP

IL 111

TOWNSHIP ROAD 354

IL 111

TR 224

TR 440

TR 328

WILLIAMSON RD/SBI

ILL 4

ILL 108

ILL 4

ILL 4

IL 111

ILL 108

IL 111

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