County profile · official public datasets

Marion County, IL

296 public highway bridges tracked in the FHWA National Bridge Inventory: 62.5% rated Good, 31.1% Fair, 6.4% Poor.

296
Public bridges: 62.5%
Good condition: 6.4%
Poor condition

The verdict

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

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

Top 32%
lowest Poor share in state: 6.4%
Poor-condition share: 296
public highway bridges: 1973
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.

Marion County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Marion County ranks #33 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 6.4%). Marion County, Illinois contains 296 public highway bridges. Roughly 62.5% are rated “Good,” 31.1% “Fair,” and 6.4% “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

296

Public highway bridges in Marion County

Good condition

62.5%

185 of 296 rated 7-9

Fair condition

31.1%

92 of 296 rated 5-6

Poor condition

6.4%

19 of 296 rated 4 or below

In-state Poor-share rank

#33 of 102

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

Condition distribution

Share of 296 NBI-tracked bridges by lowest applicable component rating.

Good

62.5% (185)

Fair

31.1% (92)

Poor

6.4% (19)

Marion County's Poor-condition bridges carry 8,285 vehicle crossings a day

That is 1.7% of the county's reported daily bridge traffic on 6.4% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 436 crossings a day against 1,404 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 295 of 296 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

44.3% of Marion County's bridges have passed the 50-year mark

131 of the 296 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 62.5% 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 47.1% of the county's Poor-condition bridge traffic

IL 161 - FAP 805 over FAI-57, built 1968, carries 3,900 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 19-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 8,285 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1900s

32
1910s

2
1920s

6
1930s

5
1940s

6
1950s

18
1960s

48
1970s

30
1980s

52
1990s

39
2000s

36
2010s

18
2020s

4

What this shows Construction peaked in the 1980s, when 52 of the county's bridges still in the inventory were built, which is 17.6% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year is 1973, 6 years older than the Illinois average of 1979.

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

The 5 Illinois counties nearest Marion County in number of bridges, with their condition splits. Its 6.4% Poor share is the 2nd-lowest of these 6. Its average build year of 1973 against a peer-group mean of 1980 is 7 years older.

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

Bridge inventory size and condition shares for Marion County and the 5 Illinois counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Coles County	304	39.5%	51.6%	8.9%	1981
Knox County	304	49.3%	39.5%	11.2%	1982
Ford County	302	55.6%	38.1%	6.3%	1983
Marion County (this page)	296	62.5%	31.1%	6.4%	1973
Hancock County	292	41.8%	38%	20.2%	1977
Logan County	292	29.8%	62%	8.2%	1975

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

Similar inventory size

Nearest county inventories outside IL (296 bridges here).

Vigo County, IN · 296 bridges
Story County, IA · 296 bridges
Guadalupe County, TX · 296 bridges
Clark County, WI · 296 bridges

Similar average build year

Nearest mean year-built outside IL (1973 here).

Jefferson County, AL · avg 1973 · 1,068 bridges
Erie County, NY · avg 1973 · 906 bridges
Davidson County, TN · avg 1973 · 832 bridges
Lancaster County, PA · avg 1973 · 801 bridges

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

All 296 Good 185 Fair 92 Poor 19

Good-condition bridges (185)

Sort:

Marion County Bridge Snapshot

Condition distribution

Marion County's Poor-condition bridges carry 8,285 vehicle crossings a day

44.3% of Marion County's bridges have passed the 50-year mark

One structure carries 47.1% of the county's Poor-condition bridge traffic

How Marion 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 (185)

TR 181

TR 335A

TR 117

CH 13

TR 64

TR 333

TR 119

TR 388

TR 528

TR 431B

TR 249B

FAS 2789

TR 15

TR 323

TR 6

FAU 8557/BOONE ST

TR 212

TR 98

FAU 8557

CH 5

TR 181

TR 22

FAS 2789

FAS 2789

CH-20

CH-20

TR 388

TR 395

SEVEN HILLS TR 120

TR 268

TR 486

TR 254

TR 119

TR 442 D

TR 226A Jezek Rd

TR 304A

TR 297 River Rd

TR 530 Foster Ln

TR 360 (Gentry Roa

TR 94 Farthing Roa

FAS-787

FAS-2719

TR 171

CH-13

TR 86

TR 460

FAU-8613

SOUTH PINE ST

TR-70

TR-214

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