County profile · official public datasets

Macon County, IL

346 public highway bridges tracked in the FHWA National Bridge Inventory: 25.7% rated Good, 58.7% Fair, 15.6% Poor.

346
Public bridges: 25.7%
Good condition: 15.6%
Poor condition

The verdict

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

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

93rd
of 102 on Poor share: 15.6%
Poor-condition share: 346
public highway bridges: 1984
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.

Macon County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Macon County ranks #93 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 15.6%). Macon County, Illinois contains 346 public highway bridges. Roughly 25.7% are rated “Good,” 58.7% “Fair,” and 15.6% “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

346

Public highway bridges in Macon County

Good condition

25.7%

89 of 346 rated 7-9

Fair condition

58.7%

203 of 346 rated 5-6

Poor condition

15.6%

54 of 346 rated 4 or below

In-state Poor-share rank

#93 of 102

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

Condition distribution

Share of 346 NBI-tracked bridges by lowest applicable component rating.

Good

25.7% (89)

Fair

58.7% (203)

Poor

15.6% (54)

Macon County's Poor-condition bridges carry 81,150 vehicle crossings a day

That is 9.4% of the county's reported daily bridge traffic on 15.6% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 1,503 crossings a day against 1,358 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 346 of 346 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

19.7% of Macon County's bridges have passed the 50-year mark

68 of the 346 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 25.7% 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 25.8% of the county's Poor-condition bridge traffic

US 36(FAP 320) over LAKE SHORE DR(U 7390, built 1954, carries 20,900 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 54-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 81,150 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

9
1920s

7
1930s

2
1940s

2
1950s

7
1960s

27
1970s

87
1980s

75
1990s

38
2000s

48
2010s

34
2020s

10

What this shows Construction peaked in the 1970s, when 87 of the county's bridges still in the inventory were built, which is 25.1% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year is 1984, 5 years newer than the Illinois average of 1979.

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

The 5 Illinois counties nearest Macon County in number of bridges, with their condition splits. Its 15.6% Poor share is the 5th-lowest of these 6. Its average build year of 1984 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 Macon County and the 5 Illinois counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Peoria County	352	24.1%	57.7%	18.2%	1983
Macon County (this page)	346	25.7%	58.7%	15.6%	1984
DuPage County	344	37.5%	54.4%	8.1%	1985
Kankakee County	344	40.1%	53.5%	6.4%	1982
Stephenson County	342	61.1%	36.3%	2.6%	1977
Kane County	336	48.2%	45.5%	6.3%	1986

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

Similar inventory size

Nearest county inventories outside IL (346 bridges here).

Dubuque County, IA · 346 bridges
Whitman County, WA · 347 bridges
Navarro County, TX · 345 bridges
Fillmore County, MN · 348 bridges

Similar average build year

Nearest mean year-built outside IL (1984 here).

Hennepin County, MN · avg 1984 · 936 bridges
Duval County, FL · avg 1984 · 831 bridges
El Paso County, CO · avg 1984 · 686 bridges
Bell County, TX · avg 1984 · 660 bridges

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

All 346 Good 89 Fair 203 Poor 54

Good-condition bridges (89)

Sort:

Macon County Bridge Snapshot

Condition distribution

Macon County's Poor-condition bridges carry 81,150 vehicle crossings a day

19.7% of Macon County's bridges have passed the 50-year mark

One structure carries 25.8% of the county's Poor-condition bridge traffic

How Macon 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

Good-condition bridges (89)

CH 34 WALKER RD

FAS 552

TR 146(SAWYER RD)

TR 3

TR 136

FAS-549A CH-20

IL 105 (EB)(FAP 74

IL 105 (WB)(FAP 74

FAP 322 (US 51)

IL 121 (FAP 320)

TR 65

TR 75

TR 2

TR 271 Crosson Rd

TR 20 A

TR 263(RIDLEN RD)

TR 11 B

TR 11 B

TR 46

TR 1(HILVETY RD)

FAS 549A(CH20)

TR 268(OAKLEY RD)

FAS 1544 (CH 24)

CH 19 (FAS 555)

TR 34

TR 27A

FAS 548

TR 226

TR 255

FAS 548

TR 34 (LINCOLN MEM

FAS 544A (CH 25)

TR 56 (GLASGOW RD)

TR 23 (NEWBURG RD)

TR 42BNEVADA RD

MUNI 0900(HARRYLAN

TR 52B

TR 256 FORT DANIEL

TR 153

FAS 554 (CH 32)

TR 265(KOSSIECK RD

CH 29 (BOODY RD)

FAS 546/CH 21

FAU-7411

FAS-548A (CH-38)

FAU 7413

CANTRELL RD(FAU735

TR 55(CUNDIFF RD)

TR 42

FAS 1538/WYCKLES R

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