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Bridge conditions in Winnebago County, Illinois

465 inventoried bridges · 32 rated poor · 2025 National Bridge Inventory

United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled August 20, 2026

The federal inventory lists 465 bridges in Winnebago County: 142 rated good, 291 fair, and 32 poor.

32 of the 465 bridges in Winnebago County, Illinois, are rated in poor condition (6.9%) in the 2025 National Bridge Inventory, as of August 20, 2026.
142 bridges (30.5%) are rated good and 291 (62.6%) fair.
The median Winnebago County bridge was built in 1975.
The busiest poor-rated bridge is I-39 SB over Harrison Ave (built 1963), carrying about 25,450 vehicles a day.

Good 30.5% · Fair 62.6% · Poor 6.9% of 465 bridges

Bridges rated poor

Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.

Bridge	Built	Vehicles/day	Condition
I-39 SB over Harrison Ave	1963	25,450	Poor
I-39 NB over Harrison Ave	1963	21,150	Poor
Ill 251 S B over UP RR	1967	13,000	Poor
Ill 251 N B over UP RR	1967	13,000	Poor
Auburn St. over Kent Creek	1930	12,400	Poor
Roscoe Rd over Rock River	1967	10,700	Poor
11TH Street over Keith Creek	1915	9,300	Poor
Springfield Ave over N Fork Kent Creek	1959	8,500	Poor
Latham-ralston Rd over Rock River	1969	8,200	Poor
N 3RD St Ext to 2N over SB Ramp to N 6TH St	1963	8,200	Poor
15TH Ave over Rock River	1980	5,750	Poor
Winnebago Street over Kent CR & RR Tracks	1982	4,900	Poor
Prairie Hill Rd over Rock River	1966	4,200	Poor
Il 70 over Trib. of Pecatonica	1982	3,500	Poor
Ill 70 over Trib. of Pecatonica	1982	3,500	Poor
Ill 70 over Trib. of Pecatonica	1982	2,950	Poor
Cunningham Rd over Cn RR	1955	2,650	Poor
Meridian Rd over Cn RR	1954	2,450	Poor
Meridian Rd over Pecatonicariver	1973	1,650	Poor
Liberty Dr over NW Drainageway	1962	1,400	Poor
Gilbert Ave over NW Drainageway	1962	1,150	Poor
Hamborg Road over Stonebridge Trail	1981	1,100	Poor
Corbin St over Kent Creek	1937	950	Poor
Gleasman Road over Unnamed Creek	1935	800	Poor
Saunders Rd over Unnamed Creek	1957	800	Poor
Simpson Road over Fullers CR	1959	700	Poor
Kilbuck Bluff Fp over Br Kilbuck CR	1926	475	Poor
Centerville Road over So Fork Kent Creek	1928	400	Poor
8TH Av over Keith Creek	1919	375	Poor
Yale Bridge Rd over Unnamed Creek	1932	325	Poor
Jonathan Ave over NW Drainageway	1962	200	Poor
Goeke Road over Pink Creek	1999	75	Poor

Busiest bridges in the county

Bridge	Built	Vehicles/day	Condition
I-39 & US 20 over Madigan Creek	1963	50,900	Fair
I-90 N B over US 20 Br	2009	36,350	Good
I-90 S B over US 20 Br	2009	36,350	Good
US 20 W B over Ill 251 (11TH St)	1960	36,000	Fair
I-90 over Stream	1958	34,100	Good
US 20 E B over Kishwaukee St.	1960	32,000	Fair
US 20 W B over Kishwaukee St.	1960	32,000	Fair
US 20 E B over Il RR	1960	32,000	Fair
US 20 W B over Il RR	1960	32,000	Fair
US 20 E B over Ill 251 (11TH St)	1960	32,000	Fair

Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.

All of Illinois: Illinois bridge conditions by county · every download on the data page.

Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.