66TH Street over M Br Black River
Allegan County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- 66TH Street over M Br Black River in Allegan County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 5 (fair condition) on the 0-9 scale.
- It was built in 1949, making it 76 years old at the 2025 inventory.
- It carries about 1,133 vehicles a day (traffic count year 2003).
- Its listed owner is the county highway agency.
- It is one of 144 of the 245 inventoried bridges in Allegan County rated fair (58.8%); 41 (16.7%) are rated poor.
- Its traffic status in the 2025 inventory is posted for load (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated September 2023, 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 → (42.43973, -86.18759)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 64 ft |
| Location | S of 103RD Ave |
| NBI structure number | 000000000000190 |
| Condition class | Fair |
| Traffic status (item 41) | Posted for load |
| Last inspection (item 90) | September 2023 |
| Inspection interval (item 91) | 24 months |
| Scour (item 113) | 5: foundations stable, scour within the limits of the footing or piles |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Allegan County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US-131 NB over Kalamazoo River | 1996 | 27,941 | Fair |
| US-131 SB over Kalamazoo River | 1996 | 27,941 | Fair |
| US-131 NB over Grand Elk RR | 1960 | 27,941 | Fair |
| US-131 SB over Grand Elk RR | 1960 | 27,941 | Poor |
| I-196 E & US-31 N over Kalamazoo River | 1964 | 24,400 | Fair |
| M-89 (allegan St) over Kalamazoo Riv Mill Race | 2012 | 21,300 | Fair |
All bridges nearby: Allegan County, MI bridge conditions · every bridge in Allegan County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.