County profile · official public datasets

Madison County, IL

523 public highway bridges tracked in the FHWA National Bridge Inventory: 49.3% rated Good, 42.3% Fair, 8.4% Poor.

523
Public bridges: 49.3%
Good condition: 8.4%
Poor condition

The verdict

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

Madison County posts a higher-than-median Poor-condition share among rated counties in the state across large county bridge inventory.

60th
of 102 on Poor share: 8.4%
Poor-condition share: 523
public highway bridges: 1979
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.

Madison County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Madison County ranks #60 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.4%). Madison County, Illinois contains 523 public highway bridges. Roughly 49.3% are rated “Good,” 42.3% “Fair,” and 8.4% “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

523

Public highway bridges in Madison County

Good condition

49.3%

258 of 523 rated 7-9

Fair condition

42.3%

221 of 523 rated 5-6

Poor condition

8.4%

44 of 523 rated 4 or below

In-state Poor-share rank

#60 of 102

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

Condition distribution

Share of 523 NBI-tracked bridges by lowest applicable component rating.

Good

49.3% (258)

Fair

42.3% (221)

Poor

8.4% (44)

Madison County's Poor-condition bridges carry 199,650 vehicle crossings a day

That is 4.8% of the county's reported daily bridge traffic on 8.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 4,538 crossings a day against 7,599 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 522 of 523 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

39.8% of Madison County's bridges have passed the 50-year mark

208 of the 523 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 49.3% 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 12.5% of the county's Poor-condition bridge traffic

FAI 270 EB over COUNTY DITCH, built 1963, carries 24,900 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 44-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 199,650 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

12
1910s

3
1920s

6
1930s

19
1940s

12
1950s

33
1960s

101
1970s

47
1980s

91
1990s

76
2000s

71
2010s

41
2020s

11

What this shows Construction peaked in the 1960s, when 101 of the county's bridges still in the inventory were built, which is 19.3% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1979) matches the Illinois average (1979).

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

The 5 Illinois counties nearest Madison County in number of bridges, with their condition splits. Its 8.4% Poor share is the 3rd-lowest of these 6. Its average build year of 1979 against a peer-group mean of 1978 is in line with the group.

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

Bridge inventory size and condition shares for Madison County and the 5 Illinois counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Livingston County	579	51.8%	39.9%	8.3%	1978
Iroquois County	570	46.5%	39.1%	14.4%	1980
LaSalle County	528	39.4%	48.3%	12.3%	1978
Madison County (this page)	523	49.3%	42.3%	8.4%	1979
Vermilion County	494	27.7%	65%	7.3%	1979
St. Clair County	486	50%	40.9%	9.1%	1977

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

Similar inventory size

Nearest county inventories outside IL (523 bridges here).

Rapides County, LA · 523 bridges
Kent County, MI · 523 bridges
Williamson County, TN · 520 bridges
New Castle County, DE · 527 bridges

Similar average build year

Nearest mean year-built outside IL (1979 here).

Pima County, AZ · avg 1979 · 1,150 bridges
Jefferson County, KY · avg 1979 · 662 bridges
Spartanburg County, SC · avg 1979 · 638 bridges
McPherson County, KS · avg 1979 · 586 bridges

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

All 523 Good 258 Fair 221 Poor 44

Poor-condition bridges (44)

Sort:

Madison County Bridge Snapshot

Condition distribution

Madison County's Poor-condition bridges carry 199,650 vehicle crossings a day

39.8% of Madison County's bridges have passed the 50-year mark

One structure carries 12.5% of the county's Poor-condition bridge traffic

How Madison 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

Poor-condition bridges (44)

SILVER CRK RD/TR 1

GORENZ DR/TR 143

OR-5 ChainOfRocksR

CNTR GROVE/ FAU 88

TR 172

IL 140

ZILLES RD/ TR 392

TR 115 (HARRIS LAN

FAI 270 EB

LOWR MARINE RD/TR2

TR 288

BROWN ST./ FAU 896

LEE RD/ TR 89

BUCKEYE RD/ TR 371

I-255 NB

I-255 SB

N SEMINARY /FAU 89

CH 49 WIESEMAN RD.

FAS 773/ ALHAMBRA

IL 111

FAIRMONT LANE

FAI 270 WB

CH61/AIRPORT ROAD

CH 31 ELLIS RD

TR 167 ROCK HILL

IL 111/3-HOMER ADA

CH 32 LEBANON RD

ELM ST./ FAU 8989

IL 4

CH 21 STAUNTON RD

ILL 111 SB

ALBY ST/ FAU 8988

CH 14 SHERRY CREEK

BLACK LANE ramp

MAPLE GROVE RD/TR2

N SIU ENT RD NB

N SIU ENT RD SB

IL 157 / IL 162

CEDAR RD/ TR 276

TR 194/LONGHI ROAD

GOODALL RD/ TR 227

MS-1980 Willow Crk

IL 140

STONEBROOKE DR

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