Algonquin Road over Crystal Creek
McHenry County, Illinois · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Algonquin Road over Crystal Creek in McHenry County, Illinois, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 5 (fair condition) on the 0-9 scale.
- It was built in 2004, making it 21 years old at the 2025 inventory.
- It carries about 31,600 vehicles a day (traffic count year 2023).
- Its listed owner is the county highway agency.
- It is one of 87 of the 227 inventoried bridges in McHenry County rated fair (38.3%); 48 (21.1%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- It was rated good in the 2024 inventory and is now fair (deck 7 to 6, superstructure 8 to 5).
- Its most recent inspection on record is dated October 2024, on a 24-month routine inspection cycle.
- 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 → (42.17603, -88.30775)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 6 | Satisfactory condition |
| Superstructure | 8 | 5 | Fair condition |
| Substructure | 8 | 8 | Very good condition |
Bridge details
| Structure | Prestressed concrete multiple box beam |
| Length | about 60 ft |
| Location | 02M W of Pyott |
| NBI structure number | 056316500000000 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | October 2024 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 8: foundations stable, scour above the top of the footing |
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 Gravel Pit Creek | 2004 | 31,600 | Fair |
| Rakow Rd (ch V-29) over Crystal Creek | 1994 | 30,600 | Good |
| Il 31 & 120 over Boone Creek | 1990 | 30,300 | 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.