Ch 4 (500 N) over I-39/US 51

Marshall County, Illinois · rated Fair in the 2025 National Bridge Inventory

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

• Ch 4 (500 N) over I-39/US 51 in Marshall County, Illinois, is rated in fair condition in the 2025 National Bridge Inventory (as of August 20, 2026).
• Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
• It was built in 1989, making it 36 years old at the 2025 inventory.
• It carries about 650 vehicles a day (traffic count year 2024).
• Its listed owner is the state highway agency.
• It is one of 71 of the 155 inventoried bridges in Marshall County rated fair (45.8%); 19 (12.3%) are rated poor.
• A fair rating means the lowest-rated major component scores 5 or 6 on FHWA's 0-9 scale: some deterioration or minor section loss, but the structure is sound. It is the middle class, not a warning.

View this bridge on a map → (40.9988, -89.05455)

Component ratings

Bridge details

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

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