County profile · official public datasets

Scott County, IL

99 public highway bridges tracked in the FHWA National Bridge Inventory: 54.5% rated Good, 38.4% Fair, 7.1% Poor.

99
Public bridges: 54.5%
Good condition: 7.1%
Poor condition

The verdict

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

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

Top 43%
lowest Poor share in state: 7.1%
Poor-condition share: 99
public highway bridges: 1983
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.

Scott County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Scott County ranks #44 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.1%). Scott County, Illinois contains 99 public highway bridges. Roughly 54.5% are rated “Good,” 38.4% “Fair,” and 7.1% “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

Public highway bridges in Scott County

Good condition

54.5%

54 of 99 rated 7-9

Fair condition

38.4%

38 of 99 rated 5-6

Poor condition

7.1%

7 of 99 rated 4 or below

In-state Poor-share rank

#44 of 102

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

Condition distribution

Share of 99 NBI-tracked bridges by lowest applicable component rating.

Good

54.5% (54)

Fair

38.4% (38)

Poor

7.1% (7)

Scott County's Poor-condition bridges carry 5,350 vehicle crossings a day

That is 4.5% of the county's reported daily bridge traffic on 7.1% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 764 crossings a day against 749 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 99 of 99 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

21.2% of Scott County's bridges have passed the 50-year mark

21 of the 99 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 54.5% 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 51.4% of the county's Poor-condition bridge traffic

OLD US 36 over WALNUT CREEK, built 1940, carries 2,750 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 7-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 5,350 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

1920s

2
1930s

2
1940s

2
1950s

4
1960s

7
1970s

18
1980s

32
1990s

15
2000s

9
2010s

7
2020s

1

What this shows Construction peaked in the 1980s, when 32 of the county's bridges still in the inventory were built, which is 32.3% of those with a recorded year. That cohort is now 35 to 44 years old in the 2024 inventory. Its average build year (1983) matches the Illinois average (1979).

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

The 5 Illinois counties nearest Scott County in number of bridges, with their condition splits. Its 7.1% Poor share is the 3rd-lowest of these 6. Its average build year of 1983 against a peer-group mean of 1982 is in line with the group.

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

Bridge inventory size and condition shares for Scott County and the 5 Illinois counties closest to it in inventory size
County	Bridges	Good	Fair	Poor	Avg. built
Boone County	109	56%	37.6%	6.4%	1986
Pulaski County	108	35.2%	56.5%	8.3%	1981
Scott County (this page)	99	54.5%	38.4%	7.1%	1983
Alexander County	93	26.9%	64.5%	8.6%	1981
Stark County	93	57%	37.6%	5.4%	1983
Menard County	89	40.4%	49.4%	10.1%	1980

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

Similar inventory size

Nearest county inventories outside IL (99 bridges here).

Washington County, FL · 99 bridges
Crisp County, GA · 99 bridges
Harris County, GA · 99 bridges
Newton County, GA · 99 bridges

Similar average build year

Nearest mean year-built outside IL (1983 here).

Dallas County, TX · avg 1983 · 3,230 bridges
Bexar County, TX · avg 1983 · 2,342 bridges
Sedgwick County, KS · avg 1983 · 1,333 bridges
Bernalillo County, NM · avg 1983 · 496 bridges

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

All 99 Good 54 Fair 38 Poor 7

Fair-condition bridges (38)

Sort:

Scott County Bridge Snapshot

Condition distribution

Scott County's Poor-condition bridges carry 5,350 vehicle crossings a day

21.2% of Scott County's bridges have passed the 50-year mark

One structure carries 51.4% of the county's Poor-condition bridge traffic

How Scott 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

Fair-condition bridges (38)

ILL 106

CH 4

TR 84

TR 74

CH 14

TR 140

CH 14

CH 4

TR 54

TR 42

FAI 72 WB

ILL 100

OLD US 36

FAI 72

CH 13

TR 154

TR 136

TR 79

TR 104

TR 59

TR 55B

TR 23

OLD US 36

I-72/US 36(WB)

I-72/US 36(EB)

FAS 605

ILL 100

FAI 72 EB

FAI 72 WB

TR 90

ILL 106

IL 100

US 67 SB

US 67 NB

FAI 72 WB

FAI 72 EB

FAI 72 WB

FAI 72 EB

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