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

Good-condition bridges (87)

CH 63E

Good

Over: LAKE FORK CREEK

1 MI E BROADWELL, Logan, IL

Built 1977 Load: 37.3 t ADT: 300

IL 10

Good

Over: SALT SPRING BRANCH

1.2M E IL 121, Logan, IL

Built 1991 Load: 37.9 t ADT: 2,200

FAS 1774

Good

Over: TRIB BRAINARDS BR

2 M N LINCOLN, Logan, IL

Built 2006 Load: 37.9 t ADT: 1,700

EMDEN RD

Good

Over: I-155

1M S IL 136, Logan, IL

Built 1991 Load: 38.2 t ADT: 325

OLD IL 121

Good

Over: PRAIRIE CREEK

1.0 MI NW HARTSBURG, Logan, IL

Built 2004 Load: 38.2 t ADT: 700

TR 79

Good

Over: FAI 155

1.9MI N I-155/I-55, Logan, IL

Built 1986 Load: 38.9 t ADT: 20

FAS-1464 (CH-16)

Good

Over: Prairie Creek Ditch

0.04 S County Line, Logan, IL

Built 2018 Load: 38.9 t ADT: 225

CH S27

Good

Over: I-55

3.1 E I155/1 N BL 55, Logan, IL

Built 1973 Load: 39.2 t ADT: 1,150

NEW HOLLAND-MIDDLE

Good

Over: SUGAR CK OVERFLOW

1.5 M S NEW HOLLAND, Logan, IL

Built 1963 Load: 39.2 t ADT: 600

TR 65A

Good

Over: I-55/UP RR/W FR RD

LAWNDALE 3.5 N BUS55, Logan, IL

Built 1974 Load: 39.5 t ADT: 100

US 136

Good

Over: PRAIRIE CREEK

0.4 MI W I 55/US 136, Logan, IL

Built 2004 Load: 39.5 t ADT: 2,350

FAP 717 (IL 10)

Good

Over: Ditch

.8 mi E Mason Co Ln, Logan, IL

Built 2023 Load: 39.5 t ADT: 1,400

LINCOLN PKWY.

Good

Over: ICRR

N EDGE LINCOLN, Logan, IL

Built 1996 Load: 40.2 t ADT: 4,950

TR-196

Good

Over: SALT CR TRIB

2.5 NW MT PLKSKY, Logan, IL

Built 2006 Load: 40.8 t ADT: 100

OLD ILL 121

Good

Over: BR KICKAPOO CREEK

0.4 MI N LINCOLN, Logan, IL

Built 1998 Load: 41.5 t ADT: 1,700

OLD ILL 121

Good

Over: BR KICKAPOO CREEK

0.3 MI N LINCOLN, Logan, IL

Built 1998 Load: 41.5 t ADT: 1,700

OLD ILL 121

Good

Over: BR KICKAPOO CREEK

0.5 MI N LINCOLN, Logan, IL

Built 1998 Load: 41.5 t ADT: 1,700

FAS 564 (CH 22)

Good

Over: Trib to Sugar Creek

0.17 mi N IL 10, Logan, IL

Built 2018 Load: 41.5 t ADT: 300

IL 121

Good

Over: BRANCH SALT CREEK

0.8 MI N MT PULASKI, Logan, IL

Built 1998 Load: 41.8 t ADT: 3,500

FAS 561

Good

Over: Deer Creek

1 MI S of Lincoln, Logan, IL

Built 2019 Load: 41.8 t ADT: 800

Jefferson Street

Good

Over: Brainards Branch

0.46 mi N of IL 10, Logan, IL

Built 2019 Load: 41.8 t ADT: 550

ROCKY FORD RD

Good

Over: SALT CR

5 W 1.5 MI S LINCOLN, Logan, IL

Built 1985 Load: 42.8 t ADT: 350

BL 55/ OLD 66 NB

Good

Over: SALT CREEK

1.9 S IL 10 LINCOLN, Logan, IL

Built 2014 Load: 43.1 t ADT: 4,650

ILL 121

Good

Over: DEER CREEK

1.3MI SE LINCOLN, Logan, IL

Built 1999 Load: 43.4 t ADT: 3,650

EMDEN-BURTON VIEW

Good

Over: PRAIRIE CR TRIB

2 MI S EMDEN, Logan, IL

Built 1999 Load: 43.4 t ADT: 450

E FR RD OF I-155

Good

Over: S FK PRAIRIE CREEK

.2M S US 136, Logan, IL

Built 1990 Load: 46.0 t ADT: 700

WAYNESVILLE RD

Good

Over: LOCAL DRAINAGE

3.5 MI SE ATLANTA, Logan, IL

Built 1997 Load: 46.7 t ADT: 325

TR 240

Good

Over: LAKE FORK CK

4.5 S 1 MI E MT PLSK, Logan, IL

Built 1964 Load: 47.0 t ADT: 50

ARMINGTON SPUR

Good

Over: SUGAR CREEK

TAZWL CL 1M S ARMGTN, Logan, IL

Built 2004 Load: 48.3 t ADT: 425

1842nd Av(TR 268)

Good

Over: Local Drainage

1.3 mi S IL 121, Logan, IL

Built 2019 Load: 49.9 t ADT: 50

CH 53 E

Good

Over: TRIB TO LAKE FORK

2 M E BROADWELL, Logan, IL

Built 2010 Load: 51.2 t ADT: 300

FAP 717 (IL 10)

Good

Over: Sugar Creek Overflow

0.05 mi E TR 44, Logan, IL

Built 2015 Load: 54.4 t ADT: 2,000

FAS 1774 {OLD 121}

Good

Over: KIKAPOO CREEK

3 MILE NORTH LINCOLN, Logan, IL

Built 2006 Load: 55.7 t ADT: 1,700

I-155

Good

Over: TRIB SUGAR CREEK

1.5M NW I-55, Logan, IL

Built 1986 Load: 55.7 t ADT: 10,600

IL 10

Good

Over: DEER CREEK

4.5 M E OF IL 121, Logan, IL

Built 2010 Load: 59.9 t ADT: 1,300

I-55

Good

Over: CLEAR CREEK

1.5M N ATLANTA INT, Logan, IL

Built 1976 Load: 79.7 t ADT: 21,600

I-155 & RAMPS B &

Good

Over: N FK PRAIRIE CREEK

.1M N US 136, Logan, IL

Built 1991 Load: 91.0 t ADT: 6,800

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

Related

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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.