County profile · official public datasets

Logan County, IL

292 public highway bridges tracked in the FHWA National Bridge Inventory: 29.8% rated Good, 62% Fair, 8.2% Poor.

292
Public bridges
29.8%
Good condition
8.2%
Poor condition

The verdict

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

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

56th
of 102 on Poor share
8.2%
Poor-condition share
292
public highway bridges
1975
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.

Logan County Bridge Snapshot

According to the Federal Highway Administration's 2024 National Bridge Inventory, Logan County ranks #56 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 8.2%). Logan County, Illinois contains 292 public highway bridges. Roughly 29.8% are rated “Good,” 62% “Fair,” and 8.2% “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

292

Public highway bridges in Logan County

Good condition

29.8%

87 of 292 rated 7-9

Fair condition

62%

181 of 292 rated 5-6

Poor condition

8.2%

24 of 292 rated 4 or below

In-state Poor-share rank

#56 of 102

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

Condition distribution

Share of 292 NBI-tracked bridges by lowest applicable component rating.

Good
29.8% (87)
Fair
62% (181)
Poor
8.2% (24)

Logan County's Poor-condition bridges carry 9,370 vehicle crossings a day

That is 1.5% of the county's reported daily bridge traffic on 8.2% of its bridges: Poor-condition structures carry less traffic than their share of the inventory. Each Poor bridge averages 390 crossings a day against 1,239 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 291 of 292 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.

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

146 of the 292 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 29.8% 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 62.2% of the county's Poor-condition bridge traffic

I-155 & RAMPS A & over S FK PRAIRIE CREEK, built 1990, carries 5,825 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 24-bridge count understates how much of the daily burden sits on a single crossing.

Share is of the 9,370 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.

When Logan County's bridges were built

292 bridges with a recorded construction year, grouped by decade

bridges

What this shows Construction peaked in the 1970s, when 72 of the county's bridges still in the inventory were built, which is 24.7% of those with a recorded year. That cohort is now 45 to 54 years old in the 2024 inventory. Its average build year (1975) matches the Illinois average (1979).

Source FHWA National Bridge Inventory (year built) As of 2024 NBI release

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

The 5 Illinois counties nearest Logan County in number of bridges, with their condition splits. Its 8.2% Poor share is the 3rd-lowest of these 6. Its average build year of 1975 against a peer-group mean of 1979 is in line with the group.

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

Bridge inventory size and condition shares for Logan County and the 5 Illinois counties closest to it in inventory size
County Bridges Poor
Coles County 304 8.9%
Knox County 304 11.2%
Ford County 302 6.3%
Marion County 296 6.4%
Hancock County 292 20.2%
Logan County (this page) 292 8.2%

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

Similar inventory size

Nearest county inventories outside IL (292 bridges here).

Similar average build year

Nearest mean year-built outside IL (1975 here).

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

All 292 Good 87 Fair 181 Poor 24

Poor-condition bridges (24)

SKUNK HOLLOW RD

Poor

Over: KICKAPOO CREEK TRIB

3 N .5 E LINCOLN, Logan, IL

Built 1900 Load: 5.5 t ADT: 50

TR 218

Poor

Over: LAKE FORK CK FLD PLN

2 E 2.5 MI S LAKE FK, Logan, IL

Built 1968 Load: 19.4 t ADT: 25

TR 35

Poor

Over: LOCAL DRAINAGE

2 MI S 2 MI E UNION, Logan, IL

Built 1960 Load: 21.7 t ADT: 35

TR 72

Poor

Over: PRAIRIE CREEK

.5 MI N EMDEN, Logan, IL

Built 1988 Load: 22.0 t ADT: 150

TR 188

Poor

Over: LAKE FORK CK FLD PLN

2 MI S LAKE FORK, Logan, IL

Built 1969 Load: 23.7 t ADT: 50

TR 25

Poor

Over: LOCAL DRAINAGE

3.5 MI SE UNION, Logan, IL

Built 1960 Load: 24.3 t ADT: 50

TR 218

Poor

Over: LOCAL DRAINAGE

2 E 2.5 MI S LAKE FK, Logan, IL

Built 1968 Load: 24.6 t ADT: 25

I-155 & RAMPS A &

Poor

Over: S FK PRAIRIE CREEK

.2M S US 136, Logan, IL

Built 1990 Load: 24.9 t ADT: 5,825

TR 38

Poor

Over: PRAIRIE CK

4 S 3 MI E SAN JOSE, Logan, IL

Built 1954 Load: 25.3 t ADT: 50

NEW HOLLAND-SAN JO

Poor

Over: PRAIRIE CK

4 MI N NEW HOLLAND, Logan, IL

Built 1961 Load: 25.6 t ADT: 150

PALMER AVE

Poor

Over: BRAINARDS BRANCH

0.2 MI N IL RT 10, Logan, IL

Built 1966 Load: 25.9 t ADT: 500

TR 195

Poor

Over: SALT CK TRIB

2 W 1 MI N MT PLSKI, Logan, IL

Built 1958 Load: 26.2 t ADT: 50

TR 176

Poor

Over: LAKE FORK CK FLD PLN

1 W 1.5 S MI LAKE FK, Logan, IL

Built 1965 Load: 27.7 t ADT: 100

TR-56

Poor

Over: Lake Fork Creek Trib

1 W 1 MI S ELKHART, Logan, IL

Built 1958 Load: 28.8 t ADT: 100

TR 199A

Poor

Over: LAKE FORK

4.5 E 1 MI S ELKHART, Logan, IL

Built 1978 Load: 29.5 t ADT: 225

TR 212

Poor

Over: LAKE FORK CK TRIB

1 E 1.5 MI S LAKE FK, Logan, IL

Built 1961 Load: 29.5 t ADT: 35

TR 152

Poor

Over: LAKE FORK CK TRIB

4.5 E 1 MI N ELKHART, Logan, IL

Built 1959 Load: 30.5 t ADT: 50

TR 158

Poor

Over: SALT CREEK

5 MI S LINCOLN, Logan, IL

Built 1991 Load: 31.8 t ADT: 75

SOUTH BEASON RD

Poor

Over: DEER CK BR

.25 MI E LINCOLN, Logan, IL

Built 1965 Load: 33.0 t ADT: 800

CH 34E

Poor

Over: SUGAR CR

2 MI E UNION, Logan, IL

Built 1978 Load: 34.3 t ADT: 100

CH 43E (CH 24)

Poor

Over: PRAIRIE CK

5 MI S SAN JOSE, Logan, IL

Built 1987 Load: 36.3 t ADT: 50

WAYNESVILLE ROAD

Poor

Over: KICKAPOO CREEK

1.5 S 3 MI E ATLANTA, Logan, IL

Built 1980 Load: 39.5 t ADT: 325

BL 55 (OLD US 66)

Poor

Over: I-55

BL 55 INT-SW LINCOLN, Logan, IL

Built 1973 Load: 51.8 t ADT: 500

TR 44

Poor

Over: SUGAR CK FLOOD PLAIN

2 MI WNW BURTON VIEW, Logan, IL

Built 1991 Load: 84.2 t ADT: 50

Read our methodology - how this data is sourced, computed, and verified.

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Data sourced from official public datasets. See our methodology for details. Retrieved and formatted by PlainBridges

Every figure on PlainBridges is rendered directly from federal source data, no number is typed in by an editor. This page draws directly on federal source data, no figure is typed in by an editor. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error. NBI condition categories reflect the latest reported inventory record, not a live safety, closure, or travel decision.