Thayer Road over Nippersink Creek
McHenry County, Illinois · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Thayer Road over Nippersink Creek in McHenry County, Illinois, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 3 (serious condition) on the 0-9 scale.
- It was built in 1975, making it 50 years old at the 2025 inventory.
- It carries about 800 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.
View this bridge on a map → (42.41434, -88.44195)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 3 | Serious condition |
| Superstructure | 3 | Serious condition |
| Substructure | 7 | Good condition |
Bridge details
| Structure | Concrete channel beam |
| Length | about 91 ft |
| Location | 0.3 Mi W of Il 47 |
| NBI structure number | 056311500000000 |
| Condition class | Poor |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Illinois department of transportation.
Busiest bridges in McHenry County
| 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 |
All bridges nearby: McHenry County, IL bridge conditions · every bridge in McHenry County · Illinois bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.