Total bridges
292
Public highway bridges in Logan County
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.
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
- 1900s 7
1900–1909
7 bridges
- 1920s 3
1920–1929
3 bridges
- 1930s 13
1930–1939
13 bridges
- 1940s 9
1940–1949
9 bridges
- 1950s 20
1950–1959
20 bridges
- 1960s
1960–1969
46 bridges
- 1970s
1970–1979
72 bridges
- 1980s
1980–1989
51 bridges
- 1990s
1990–1999
38 bridges
- 2000s 16
2000–2009
16 bridges
- 2010s 16
2010–2019
16 bridges
- 2020s 1
2020–2029
1 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).
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.
| 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 | 296 | 62.5% | 31.1% | 6.4% | 1973 |
| Hancock County | 292 | 41.8% | 38% | 20.2% | 1977 |
| Logan County (this page) | 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 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).
- Canyon County, ID · 292 bridges
- Jackson County, OK · 292 bridges
- Clearfield County, PA · 292 bridges
- Boone County, IN · 293 bridges
Similar average build year
Nearest mean year-built outside IL (1975 here).
- San Bernardino County, CA · avg 1975 · 1,422 bridges
- Lane County, OR · avg 1975 · 1,010 bridges
- Fulton County, GA · avg 1975 · 775 bridges
- Westmoreland County, PA · avg 1975 · 620 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (181)
TR 146
FairOver: SUGAR CK
2 MI N BELL STA, Logan, IL
Built 1987 Load: 32.4 t ADT: 100
TR 82
FairOver: PRAIRIE CK
1 E 2.5 MI S EMDEN, Logan, IL
Built 1987 Load: 32.4 t ADT: 300
TR 17
FairOver: PRAIRIE CREEK
1.5 S .5 MI W EMDEN, Logan, IL
Built 1978 Load: 32.4 t ADT: 35
TR 46
FairOver: PRAIRIE CK TRIB
4.5 MI W 1MI S HARBG, Logan, IL
Built 1979 Load: 32.4 t ADT: 20
TR 9
FairOver: PRAIRIE CREEK
1 S .5 MI E SAN JOSE, Logan, IL
Built 1982 Load: 32.4 t ADT: 50
TR 22
FairOver: PRAIRIE CK
4 S 2 MI ESAN JOSE, Logan, IL
Built 1987 Load: 32.4 t ADT: 50
TR 33
FairOver: PRAIRE CREEK
4 S 1 E SAN JOSE, Logan, IL
Built 2005 Load: 32.4 t ADT: 150
TR 44
FairOver: LOCAL DRAINAGE
2 MI S 3 MI E N HOLL, Logan, IL
Built 1975 Load: 32.4 t ADT: 50
TR 2
FairOver: SUGAR CREEK
1.5 MI SW NEW HOLLND, Logan, IL
Built 1986 Load: 32.4 t ADT: 35
TR 60
FairOver: SUGAR CREEK TRIB
1 MI NW BURTON VIEW, Logan, IL
Built 1985 Load: 32.4 t ADT: 20
TR 103
FairOver: SUGAR CREEK
2.5MI SE NEW HOLLAND, Logan, IL
Built 1995 Load: 32.4 t ADT: 20
TR 80
FairOver: SUGAR CREEK
1 E 2.5 N BURTONVIEW, Logan, IL
Built 1982 Load: 32.4 t ADT: 75
TR 106A
FairOver: SUGAR CREEK
2 MI S HARTSBURG, Logan, IL
Built 1985 Load: 32.4 t ADT: 25
TR 20A
FairOver: SOUTH FORK LAKE FORK
4.5 MI NW WARRENSBUR, Logan, IL
Built 1987 Load: 32.4 t ADT: 35
IL 121
FairOver: SALT CREEK
3.9M N IL54-MT PUL.*, Logan, IL
Built 1928 Load: 32.7 t ADT: 3,500
US 136
FairOver: W FORK SUGAR CREEK
1.2M W ARMINGTON RD, Logan, IL
Built 1936 Load: 32.7 t ADT: 1,900
I-55 NB
FairOver: SALT CREEK OVERFLOW
1.6M S IL 10, Logan, IL
Built 1973 Load: 32.7 t ADT: 13,750
I-55 SB
FairOver: SALT CREEK OVERFLOW
1.6M S IL 10, Logan, IL
Built 1973 Load: 32.7 t ADT: 13,750
NICHOLSON RD
FairOver: KICKAPOO CK
3 MI N LINCOLN, Logan, IL
Built 1970 Load: 32.7 t ADT: 400
TR 288B
FairOver: NORTH FORK
3.0 MI W LATHAM, Logan, IL
Built 1975 Load: 33.4 t ADT: 100
LINCOLN PKWY.
FairOver: BRAINARDS BRANCH
.6M N IL121 NW LNCLN, Logan, IL
Built 1939 Load: 33.7 t ADT: 4,350
OLD IL 121
FairOver: I-55
2.7 N IL10-1 N BL 55, Logan, IL
Built 1973 Load: 34.0 t ADT: 1,250
I-55 W FRONTAGE RO
FairOver: CLEAR CREEK
1.7M N ATLANTA INTCH, Logan, IL
Built 1943 Load: 34.3 t ADT: 1,400
CH-6 BEASN-CHSTNT
FairOver: SALT CK
2 MI N CHESTNUT, Logan, IL
Built 1961 Load: 34.7 t ADT: 350
TR 128
FairOver: LAKE FORK CREEK
2 E 1 MI N BROADWELL, Logan, IL
Built 1981 Load: 34.7 t ADT: 225
TR 95
FairOver: DEER CREEK
1.5 W 2.5 MI N BEASN, Logan, IL
Built 1973 Load: 35.0 t ADT: 50
FAI 155 SB
FairOver: ICG RR
2.7MI S I-155/IL136, Logan, IL
Built 1988 Load: 35.3 t ADT: 5,300
FAI 155 NB
FairOver: ICG RR
2.7MI S I-155/IL136, Logan, IL
Built 1988 Load: 35.3 t ADT: 5,300
TR 304
FairOver: S FORK LAKE FORK CK
1 W 2.5 MI S LATHAM, Logan, IL
Built 1969 Load: 35.6 t ADT: 25
TR 23
FairOver: PRAIRIE CK
3 S .5 MI E SAN JOSE, Logan, IL
Built 1964 Load: 35.6 t ADT: 50
FAI 155 SB
FairOver: S BR PRAIRIE CREEK
3.0MI S I-155/IL136, Logan, IL
Built 1988 Load: 36.9 t ADT: 5,300
FAI 155 NB
FairOver: S BR PRAIRIE CREEK
3.0MI S I-155/IL136, Logan, IL
Built 1988 Load: 36.9 t ADT: 5,300
TR 290
FairOver: KICKAPOO CRK
2.5 MI S ATLANTA, Logan, IL
Built 1980 Load: 36.9 t ADT: 75
CH E52
FairOver: I-55
.8 S IL10-1.6 W BL55, Logan, IL
Built 1973 Load: 37.6 t ADT: 1,050
IL 10
FairOver: KICKAPOO CR OVERFLOW
0.5 MI W I-55, Logan, IL
Built 1999 Load: 37.6 t ADT: 3,100
I-55 SB
FairOver: SALT CREEK
2.1M S IL10, Logan, IL
Built 1973 Load: 38.6 t ADT: 13,750
I-55 NB
FairOver: SALT CREEK
2.1M S IL10, Logan, IL
Built 1973 Load: 38.6 t ADT: 13,750
IL 121
FairOver: NORTH BR LAKE FORK
3.9M E IL54-MT PUL.*, Logan, IL
Built 1931 Load: 38.9 t ADT: 2,850
ILL 10
FairOver: PRAIRIE CREEK
.10 MI E MASON CO LN, Logan, IL
Built 2007 Load: 38.9 t ADT: 1,400
TR 252
FairOver: SUGAR CREEK
3.4 MI N.W. ATLANTA, Logan, IL
Built 1989 Load: 38.9 t ADT: 20
IL 10
FairOver: KICKAPOO CREEK
.6M W I-55, Logan, IL
Built 1999 Load: 39.2 t ADT: 3,100
PRIMM RD
FairOver: Salt Springs
1 MI S LINCOLN, Logan, IL
Built 1928 Load: 39.2 t ADT: 800
TR 44
FairOver: SUGAR CREEK
3 MI E NEW HOLLAND, Logan, IL
Built 1980 Load: 39.2 t ADT: 50
OLD IL 121
FairOver: SUGAR CREEK
2.5MI SE HARTSBURG, Logan, IL
Built 1999 Load: 39.5 t ADT: 1,200
US 136
FairOver: PRAIRIE CREEK
1.9M W I-155, Logan, IL
Built 1937 Load: 40.2 t ADT: 2,300
TR 290
FairOver: KICKAPOO CK TRIB
2 MI S ATLANTA, Logan, IL
Built 1971 Load: 40.2 t ADT: 75
IL 10
FairOver: SUGAR CREEK
3.4M E NEW HOLLAND*, Logan, IL
Built 1931 Load: 42.1 t ADT: 2,000
FAS 559A
FairOver: SUGAR CREEK
4.4 Mi N I-55, Logan, IL
Built 1976 Load: 42.8 t ADT: 250
I-55 NB
FairOver: ICRR & KICKAPOO OVFL
2.1 M E I-55/155INT, Logan, IL
Built 1974 Load: 43.4 t ADT: 10,750
I-55 SB
FairOver: ICRR & KICKAPOO OVFL
2.1 M E I-55/155INT, Logan, IL
Built 1974 Load: 43.4 t ADT: 10,750
Read our methodology - how this data is sourced, computed, and verified.
Related
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.