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.
All bridges (467)
EAST RIVERSIDE BLV
FairOver: SPRING CREEK
0.1 MI. W. OF I-90, Winnebago, IL
Built 1989 Load: 32.4 t ADT: 25,700
SPRING LAKE DR
FairOver: SPRING CREEK
.01 N OF SPRINGBROOK, Winnebago, IL
Built 1965 Load: 32.4 t ADT: 625
COACHMAN DRIVE
FairOver: KEITH CREEK
0.2 MI. N. GUILFORD, Winnebago, IL
Built 2004 Load: 32.4 t ADT: 150
W STATE ST
FairOver: KENT CR
0.06 MI W KILBURN, Winnebago, IL
Built 1979 Load: 32.4 t ADT: 6,400
KISHWAUKEE ST
FairOver: KEITH CREEK
0.12 N OF BROADWAY, Winnebago, IL
Built 2009 Load: 32.4 t ADT: 14,600
ELM AVE
FairOver: LOVES PARK CREEK
N. OF CLIFFORD AVE, Winnebago, IL
Built 1996 Load: 32.4 t ADT: 1,350
SWANSON DR
FairOver: S BR MCDONALD CRK
.2 MI S OF SWANSON R, Winnebago, IL
Built 2007 Load: 32.4 t ADT: 1,000
TR 251-ROTARY RD
FairOver: I-39 & US 51
1.5 MI N OF OGLE CO, Winnebago, IL
Built 1980 Load: 32.7 t ADT: 300
FAS1045-BAXTER RD
FairOver: I-39 & US 51
1.0 MI N OF OGLE CO, Winnebago, IL
Built 1980 Load: 32.7 t ADT: 2,250
PERRYVILLE RD
FairOver: MADIGAN CR
AT CHARLES ST, Winnebago, IL
Built 1973 Load: 32.7 t ADT: 19,200
BRADLEY RD
FairOver: SPRING CREEK
0.07 M S SPRING CR R, Winnebago, IL
Built 1977 Load: 32.7 t ADT: 350
CLIFFORD AVE
FairOver: LOVES PARK CREEK
NORTHEAST LOVES PARK, Winnebago, IL
Built 1961 Load: 32.7 t ADT: 2,700
PECATONICA ROAD
FairOver: OTTER CREEK
0.1 MI S DURAND ROAD, Winnebago, IL
Built 1971 Load: 33.0 t ADT: 10
WHEELER RD
FairOver: OTTER CREEK
1 MI N FRITZ ROAD, Winnebago, IL
Built 2009 Load: 33.0 t ADT: 525
WINSLOW RD
FairOver: SUGAR CREEK
W EDGE OF SHIRLAND, Winnebago, IL
Built 1977 Load: 33.0 t ADT: 325
MINNS DRIVE
FairOver: WILLOW CREEK
.3 MI E. ALPINE RD, Winnebago, IL
Built 1990 Load: 33.0 t ADT: 750
ILL 2
FairOver: DRAINAGE DITCH
.05 S WISC ST LN, Winnebago, IL
Built 1958 Load: 34.0 t ADT: 13,000
ILL 251 N B
FairOver: DRY CREEK
.32 MI N MCCURRY RD, Winnebago, IL
Built 1967 Load: 34.0 t ADT: 16,600
ILL 251 S B
FairOver: DRY CREEK
.32 MI N MCCURRY RD, Winnebago, IL
Built 1967 Load: 34.0 t ADT: 16,600
AUBURN RD
FairOver: BR OF KENT CREEK
0.3 MI W OF MERIDIAN, Winnebago, IL
Built 1983 Load: 34.0 t ADT: 1,300
ILL 70
FairOver: DRAINAGE DITCH
.2 MI E OF LEECH RD, Winnebago, IL
Built 1932 Load: 34.3 t ADT: 3,000
US 20 W B
FairOver: ILL 2
1 MI S OF ROCKFORD, Winnebago, IL
Built 2019 Load: 34.3 t ADT: 32,000
HARLEM RD/BAUER PK
FairOver: ICE LINE RAILROAD
0.2 MI. E. OF IL 2, Winnebago, IL
Built 1989 Load: 34.3 t ADT: 11,300
I-39 NB
FairOver: LINDEN ROAD
0.25 MI S OF US 20, Winnebago, IL
Built 1981 Load: 34.7 t ADT: 12,600
US 20 E B
FairOver: ILL 2
1 MI S OF ROCKFORD, Winnebago, IL
Built 2019 Load: 34.7 t ADT: 20,400
PRAIRIE ROAD
FairOver: FULLERS CR
AT RT 20 BYPASS, Winnebago, IL
Built 1965 Load: 34.7 t ADT: 1,550
OLD RIVER RD
FairOver: BLACKS CREEK
0.7 MI N LATHAM RD, Winnebago, IL
Built 1962 Load: 34.7 t ADT: 2,850
ILL 251 & W. FR RD
FairOver: N.BRNCH WILLOW CREEK
0.25 S JCT ILL 173, Winnebago, IL
Built 1964 Load: 35.0 t ADT: 17,300
US 20 E B
FairOver: IL RR
.5 MI W OF ILL 251, Winnebago, IL
Built 1960 Load: 35.3 t ADT: 32,000
AUBURN ST
FairOver: ROCK RIVER
0.4 MI W OF ILL 251, Winnebago, IL
Built 1938 Load: 35.3 t ADT: 22,600
ILL 70
FairOver: S BRANCH OTTER CR
0.8 MI NORTH RT 75, Winnebago, IL
Built 2010 Load: 35.6 t ADT: 2,700
WINSLOW ROAD
FairOver: SUGAR RIVER
2 MI W OF SHIRLAND, Winnebago, IL
Built 1985 Load: 35.6 t ADT: 150
ROCKTON RD
FairOver: RACCOON CREEK
2 MI W OF ROCKTON, Winnebago, IL
Built 1989 Load: 35.6 t ADT: 2,250
FRITZ RD
FairOver: UNNAMED CREEK
1 MI E RT 70, Winnebago, IL
Built 1962 Load: 35.6 t ADT: 550
ILL 251 NB
FairOver: N KINNIKINNICK CR
0.1 M S HONONEGAH RD, Winnebago, IL
Built 1967 Load: 36.0 t ADT: 27,200
ILL 251 SB
FairOver: N KINNIKINNICK CR
0.1 M S HONONEGAH RD, Winnebago, IL
Built 1967 Load: 36.0 t ADT: 27,200
IL 70
FairOver: DRAINAGE DITCH
.1 MI N SUMMERDALE, Winnebago, IL
Built 1962 Load: 36.0 t ADT: 5,000
ALPINE ROAD
FairOver: US 20 BY-PASS
SOUTH EDGE ROCKFORD, Winnebago, IL
Built 1984 Load: 36.0 t ADT: 21,400
ILL 251 NB
FairOver: S KINNIKINNICK CR
0.8 M S HONONEGAH RD, Winnebago, IL
Built 1967 Load: 36.3 t ADT: 27,200
ILL 251 SB
FairOver: S KINNIKINNICK CR
0.8 M S HONONEGAH RD, Winnebago, IL
Built 1967 Load: 36.3 t ADT: 27,200
I-39 & US 51 SB
FairOver: KISHWAUKEE RIVER
0.75 MI S BLKHAWK RD, Winnebago, IL
Built 1980 Load: 36.3 t ADT: 14,500
I-39 & US 51 NB
FairOver: KISHWAUKEE RIVER
0.75 MI S BLKHAWK RD, Winnebago, IL
Built 1981 Load: 36.3 t ADT: 14,500
PERRYVILLE RD
FairOver: UNION PACIFIC RAILRO
.2 MI N I-39, Winnebago, IL
Built 2016 Load: 36.3 t ADT: 7,450
FARM SCHOOL ROAD
FairOver: BRANCH OF PINK CREEK
0.2 MI W BEST ROAD, Winnebago, IL
Built 1963 Load: 36.3 t ADT: 50
REED AVE
FairOver: S.E. DRAINAGEWAY
0.1 MI W OF 11TH ST, Winnebago, IL
Built 1967 Load: 36.3 t ADT: 425
ALPINE RD
FairOver: FOREST HILLS RD
0.2 MI S WINDSOR RD, Winnebago, IL
Built 1972 Load: 36.6 t ADT: 16,700
MORGAN ST
FairOver: ROCK RIVER
0.3 mile E OF IL 2, Winnebago, IL
Built 2013 Load: 36.6 t ADT: 7,600
WHITMAN ST
FairOver: MADISON ST & RR
0.25 MI E OF MAIN ST, Winnebago, IL
Built 1961 Load: 36.6 t ADT: 19,400
I-39 RAMP 389
FairOver: I-39 & US 51 SB
0.35 MI S OF US 20, Winnebago, IL
Built 1981 Load: 36.9 t ADT: 4,550
CENTRAL AVE
FairOver: N FORK KENT CREEK
0.1 MI N AUBURN ST, Winnebago, IL
Built 1966 Load: 36.9 t ADT: 7,800
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.