Home › Illinois › McHenry County › Thorne Rd over Kishwaukee Riv

Thorne Rd over Kishwaukee Riv

McHenry County, Illinois · rated Poor in the 2025 National Bridge Inventory

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

Thorne Rd over Kishwaukee Riv in McHenry County, Illinois, is rated in poor condition in the 2025 National Bridge Inventory (as of August 20, 2026).
Its lowest-rated component is the deck, rated 4 (poor condition) on the 0-9 scale.
It was built in 1992, making it 33 years old at the 2025 inventory.
It carries about 275 vehicles a day (traffic count year 2021).
Its listed owner is a town or township highway agency.
It is one of 48 of the 227 inventoried bridges in McHenry County rated poor (21.1%); 48 (21.1%) are rated poor.
A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.

Component ratings


Structure	Prestressed concrete multiple box beam
Length	about 216 ft
Location	3.0 Mi W of Marengo
NBI structure number	056315100000000
Condition class	Poor

Source: FHWA National Bridge Inventory, 2025 data as reported by the Illinois department of transportation.

Bridge	Built	Vehicles/day	Condition
Il 62 over Fox River	1988	43,100	Fair
Il 31 over RR - UP	1971	34,400	Fair
Algonquin Road over Woods Creek	2004	31,600	Fair
Algonquin Road over Crystal Creek	2004	31,600	Fair
Algonquin Road over Gravel Pit Creek	2004	31,600	Fair
Rakow Rd (ch V-29) over Crystal Creek	1994	30,600	Good