Il 31 over Crystal Creek
McHenry County, Illinois · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Il 31 over Crystal Creek in McHenry County, Illinois, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 7 (good condition) on the 0-9 scale.
- It was built in 2013, making it 12 years old at the 2025 inventory.
- It carries about 17,900 vehicles a day (traffic count year 2023).
- Its listed owner is the state highway agency.
- It is one of 92 of the 227 inventoried bridges in McHenry County rated good (40.5%); 48 (21.1%) are rated poor.
- A good rating means every major component - deck, superstructure, substructure, or culvert - is rated 7 or higher on FHWA's 0-9 scale: no more than minor problems.
View this bridge on a map → (42.16864, -88.29685)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 7 | Good condition |
| Superstructure | 8 | Very good condition |
| Substructure | 8 | Very good condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 139 ft |
| Location | 0.1 M S Algonquin Rd |
| NBI structure number | 056007700000000 |
| Condition class | Good |
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.