Total bridges
467
Public highway bridges in Winnebago County
County profile · official public datasets
Winnebago County, IL
467 public highway bridges tracked in the FHWA National Bridge Inventory: 31.3% rated Good, 61.7% Fair, 7.1% Poor.
- 467
- Public bridges
- 31.3%
- Good condition
- 7.1%
- Poor condition
The verdict
According to the Federal Highway Administration's 2024 National Bridge Inventory.
Winnebago County posts a better-than-median Poor-condition share among rated counties in the state across mid-size county bridge inventory.
- Top 42%
- lowest Poor share in state
- 7.1%
- Poor-condition share
- 467
- public highway bridges
- 1978
- 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.
Winnebago County Bridge Snapshot
According to the Federal Highway Administration's 2024 National Bridge Inventory, Winnebago County ranks #43 of 102 Illinois counties with at least 5 public highway bridges on Poor-condition share (lower share ranks better; currently 7.1%). Winnebago County, Illinois contains 467 public highway bridges. Roughly 31.3% are rated “Good,” 61.7% “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.
Good condition
31.3%
146 of 467 rated 7-9
Fair condition
61.7%
288 of 467 rated 5-6
Poor condition
7.1%
33 of 467 rated 4 or below
In-state Poor-share rank
#43 of 102
Among Illinois counties with 5+ bridges, lower share ranks better
Condition distribution
Share of 467 NBI-tracked bridges by lowest applicable component rating.
Good 31.3% (146)
Fair 61.7% (288)
Poor 7.1% (33)
Winnebago County's Poor-condition bridges carry 180,060 vehicle crossings a day
That is 4.9% 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 5,456 crossings a day against 6,482 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 467 of 467 bridges in this county that report an average daily traffic count. Source: FHWA National Bridge Inventory, 2024 release.
49.5% of Winnebago County's bridges have passed the 50-year mark
231 of the 467 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 31.3% 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 14.1% of the county's Poor-condition bridge traffic
I-39 SB over HARRISON AVE, built 1963, carries 25,450 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 33-bridge count understates how much of the daily burden sits on a single crossing.
Share is of the 180,060 daily crossings on Poor-rated bridges that report a traffic count. Source: FHWA National Bridge Inventory, 2024 release.
When Winnebago County's bridges were built
467 bridges with a recorded construction year, grouped by decade
- 1900s 3
1900–1909
3 bridges
- 1910s 3
1910–1919
3 bridges
- 1920s 9
1920–1929
9 bridges
- 1930s 12
1930–1939
12 bridges
- 1940s 7
1940–1949
7 bridges
- 1950s 48
1950–1959
48 bridges
- 1960s
1960–1969
121 bridges
- 1970s
1970–1979
55 bridges
- 1980s
1980–1989
64 bridges
- 1990s 44
1990–1999
44 bridges
- 2000s 42
2000–2009
42 bridges
- 2010s
2010–2019
52 bridges
- 2020s 7
2020–2029
7 bridges
What this shows Construction peaked in the 1960s, when 121 of the county's bridges still in the inventory were built, which is 25.9% of those with a recorded year. That cohort is now 55 to 64 years old in the 2024 inventory. Its average build year (1978) matches the Illinois average (1979).
How Winnebago County compares with Illinois's closest counties by inventory size
The 5 Illinois counties nearest Winnebago County in number of bridges, with their condition splits. Its 7.1% Poor share is the 2nd-lowest of these 6. Its average build year of 1978 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 |
|---|---|---|---|---|---|
| LaSalle County | 528 | 39.4% | 48.3% | 12.3% | 1978 |
| Madison County | 523 | 49.3% | 42.3% | 8.4% | 1979 |
| Vermilion County | 494 | 27.7% | 65% | 7.3% | 1979 |
| St. Clair County | 486 | 50% | 40.9% | 9.1% | 1977 |
| Winnebago County (this page) | 467 | 31.3% | 61.7% | 7.1% | 1978 |
| Sangamon County | 466 | 56.9% | 36.9% | 6.2% | 1981 |
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 Winnebago 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 Winnebago County, both outside Illinois so the neighborhoods are not the same-state size table above.
Similar inventory size
Nearest county inventories outside IL (467 bridges here).
- Broome County, NY · 468 bridges
- Brown County, WI · 466 bridges
- Le Flore County, OK · 469 bridges
- Pecos County, TX · 470 bridges
Similar average build year
Nearest mean year-built outside IL (1978 here).
- Orange County, CA · avg 1978 · 1,164 bridges
- Sumner County, KS · avg 1978 · 659 bridges
- Allen County, IN · avg 1978 · 613 bridges
- Buncombe County, NC · avg 1978 · 555 bridges
Source: FHWA National Bridge Inventory, 2024 release. Peers floor at 10 bridges so stub inventories cannot own the match.
Fair-condition bridges (288)
BURR OAK ROAD
FairOver: UNNAMED CREEK
0.5 MI W CROCKETT RD, Winnebago, IL
Built 1971 Load: 36.9 t ADT: 1,400
PERRYVILLE RD
FairOver: LOVES PARK CREEK
.4 MI N RIVERSIDE BL, Winnebago, IL
Built 1994 Load: 36.9 t ADT: 16,700
US 20 EB
FairOver: KISHWAUKEE RIVER
.12 MI E OLD MILL RD, Winnebago, IL
Built 1963 Load: 37.3 t ADT: 14,900
US 20 WB
FairOver: KISHWAUKEE RIVER
.12 MI E OLD MILL RD, Winnebago, IL
Built 1963 Load: 37.3 t ADT: 14,900
HONONEGAH ROAD
FairOver: ILL 2
IN ROCKTON, Winnebago, IL
Built 1966 Load: 37.6 t ADT: 6,300
ROCKTON RD
FairOver: ROCKTN DAM MILL RACE
W. EDGE OF ROCKTON, Winnebago, IL
Built 1990 Load: 37.6 t ADT: 2,200
SWANSON RD
FairOver: UNNAMED STREAM
1.2 MI. E. IL 251, Winnebago, IL
Built 1977 Load: 37.6 t ADT: 3,450
ROCKTON AVE
FairOver: NW DRAINAGEWAY
0.3 MI S OF HALSTED, Winnebago, IL
Built 1962 Load: 37.9 t ADT: 8,850
HUNTER AVE
FairOver: KEITH CREEK
.01 MI N OF CHARLES, Winnebago, IL
Built 1987 Load: 37.9 t ADT: 2,150
FRITZ RD
FairOver: S FORK OTTER CREEK
0.7 MI E RT 70, Winnebago, IL
Built 1962 Load: 38.2 t ADT: 550
ILL 70
FairOver: KENT CREEK
0.1 M W SPRINGFLD RD, Winnebago, IL
Built 2003 Load: 38.6 t ADT: 4,600
MONTAGUE RD
FairOver: US RT 20
1.5 MI E MERIDIAN RD, Winnebago, IL
Built 1964 Load: 38.9 t ADT: 5,750
STATE ST
FairOver: KISHWAUKEE RIVER
IN CHERRY VALLEY, Winnebago, IL
Built 1926 Load: 38.9 t ADT: 4,350
IL 251 (FAP 734)
FairOver: UP RR
KISHWAUKEE ST-RKFORD, Winnebago, IL
Built 1991 Load: 38.9 t ADT: 15,800
IL 70
FairOver: PECATONICA RIVER
5 MI S. OF DURAND, Winnebago, IL
Built 1996 Load: 38.9 t ADT: 3,500
ILL 70
FairOver: TRIB PECATONICA RIV
.4 MI E OF JUDD RD, Winnebago, IL
Built 1982 Load: 38.9 t ADT: 3,000
MONTAGUE RD
FairOver: ROCK CREEK
0.2 M W MERIDIAN RD, Winnebago, IL
Built 1981 Load: 38.9 t ADT: 3,300
WHITMAN ST
FairOver: ROCK RIVER
0.03 MI W OF N MAIN, Winnebago, IL
Built 1960 Load: 38.9 t ADT: 19,400
PECATONICA RD
FairOver: PECATONICA RIVER
N EDGE OF PECATONICA, Winnebago, IL
Built 1985 Load: 39.2 t ADT: 2,700
US 20 W B
FairOver: IL RR
.5 MI W OF ILL 251, Winnebago, IL
Built 1960 Load: 39.5 t ADT: 32,000
HARRISON ROAD
FairOver: TUNNISON CREEK
1.9 MI N TRASK BR RD, Winnebago, IL
Built 1992 Load: 39.5 t ADT: 225
MULFORD ROAD
FairOver: KEITH CREEK
0.5 MI N GUILFORD RD, Winnebago, IL
Built 1961 Load: 39.5 t ADT: 8,700
ALPINE ROAD
FairOver: WILLOW CREEK
0.8 MI. S IL 173, Winnebago, IL
Built 1989 Load: 39.5 t ADT: 16,100
MOATE ROAD
FairOver: DRAINAGE DITCH
0.3 MI. N. FRITZ RD., Winnebago, IL
Built 1999 Load: 39.5 t ADT: 25
HARRISON AVE
FairOver: ROCK RIVER
0.2 MI E OF ILL RT 2, Winnebago, IL
Built 1975 Load: 39.5 t ADT: 10,200
CHESTNUT ST
FairOver: ROCK RIVER
0.1 MI E OF MAIN ST, Winnebago, IL
Built 1962 Load: 39.5 t ADT: 8,200
ILL 2
FairOver: DRAINAGE DITCH
1 MI N OF LATHAM RD, Winnebago, IL
Built 1989 Load: 39.9 t ADT: 9,950
ELEVATOR RD
FairOver: NO KINNIKINNICK CR
0.15 MI. E. ILL 251, Winnebago, IL
Built 1969 Load: 39.9 t ADT: 9,800
I-90 N B
FairOver: STONEBRIDGE TRAIL
1 MI E OF ROSCOE, Winnebago, IL
Built 1958 Load: 39.9 t ADT: 28,550
ILL 75
FairOver: PECATONICA RIVER
1.2 MI W MERIDIAN RD, Winnebago, IL
Built 1990 Load: 40.2 t ADT: 2,650
CROWLEY RD
FairOver: N BR OTTER CREEK
0.5 MI N FRITZ ROAD, Winnebago, IL
Built 1966 Load: 40.2 t ADT: 200
MERIDIAN RD
FairOver: BR N FK KENT CR
0.2 M N SAFFORD RD, Winnebago, IL
Built 1979 Load: 40.2 t ADT: 3,400
RIVERSIDE BLVD
FairOver: ROCK RIVER& RR
WEST LOVES PARK, Winnebago, IL
Built 1953 Load: 40.2 t ADT: 17,700
NEWBURG RD
FairOver: MANNING CREEK
0.2 W OF COUNTY LINE, Winnebago, IL
Built 1974 Load: 41.5 t ADT: 8,000
I-90 RAMP
FairOver: I-90
.25 MI N OF 20 BR, Winnebago, IL
Built 1958 Load: 41.5 t ADT: 4,600
SWANSON RD
FairOver: I-90
1.5 MI N ILL 173, Winnebago, IL
Built 1958 Load: 41.5 t ADT: 1,950
BELTLINE RD
FairOver: S CHANNEL ROCK RIV
0.23 MI SOUTH ILL 2, Winnebago, IL
Built 1986 Load: 41.8 t ADT: 10,900
IL 251
FairOver: KISHWAUKEE RIVER
AT NEW MILLFORD, Winnebago, IL
Built 1996 Load: 41.8 t ADT: 3,300
PELLEY ROAD
FairOver: FULLER CREEK
0.5 MI W OF RT 2, Winnebago, IL
Built 1962 Load: 41.8 t ADT: 550
ATWOOD ROAD
FairOver: S.KINNIKINNICK CR
0.2 MI S BURR OAK RD, Winnebago, IL
Built 1973 Load: 41.8 t ADT: 1,500
I-39 & US 20 SB
FairOver: UP RR
1.4 MI S OF I-90, Winnebago, IL
Built 1963 Load: 42.1 t ADT: 25,450
I-39 & US 20 N B
FairOver: UP RR
1.4 MI S OF I-90, Winnebago, IL
Built 1963 Load: 42.1 t ADT: 25,450
BELTLINE RD
FairOver: N CHANNEL ROCK RIVER
.04 MI SOUTH IL 2, Winnebago, IL
Built 1986 Load: 42.4 t ADT: 10,900
IL 251 W. FR. RD.
FairOver: MC DONALD CREEK
2.0 MI. N. OF IL 173, Winnebago, IL
Built 1992 Load: 42.4 t ADT: 1,350
CENTER RD
FairOver: N. BR. OTTER CREEK
0.5 MI N NORTH ST, Winnebago, IL
Built 1990 Load: 42.4 t ADT: 700
ALPINE RD
FairOver: CN RAILROAD
0.5 MI S HARRISON AV, Winnebago, IL
Built 1963 Load: 42.8 t ADT: 21,200
SCHOOL ST
FairOver: KENT CREEK
0.2 MI W OF KILBURN, Winnebago, IL
Built 1969 Load: 42.8 t ADT: 6,200
ROCKTON RD
FairOver: I-90
2.5 MI S OF ILL 75, Winnebago, IL
Built 1958 Load: 42.8 t ADT: 2,175
ILL 2
FairOver: FULLERS CREEK
0.6 MI SOUTH US 20, Winnebago, IL
Built 2011 Load: 43.4 t ADT: 15,500
ILL 251 & FR RDS
FairOver: WILLOW CREEK
1 MI S JCT ILL 173, Winnebago, IL
Built 1964 Load: 43.4 t ADT: 17,300
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.