Morrow Road over Thunder Bay River N Br
Montmorency County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Morrow Road over Thunder Bay River N Br in Montmorency County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the deck, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 2000, making it 25 years old at the 2025 inventory.
- It carries about 100 vehicles a day (traffic count year 2005).
- Its listed owner is the county highway agency.
- It is one of 8 of the 21 inventoried bridges in Montmorency County rated fair (38.1%); 0 (0.0%) are rated poor.
- Its traffic status in the 2025 inventory is open, no restriction (NBI item 41).
- Its condition class and component ratings are unchanged from the 2024 inventory.
- Its most recent inspection on record is dated November 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 → (45.179, -83.92313)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 6 | 6 | Satisfactory condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 8 | 8 | Very good condition |
Bridge details
| Structure | Prestressed concrete multiple box beam |
| Length | about 45 ft |
| Location | Sec 10 11 Montmorency Twp |
| NBI structure number | 000000000007545 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | November 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 Montmorency County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| M-32 Bs|s State St over Thunder Bay River | 2009 | 6,400 | Fair |
| M-32 over Miller Creek | 1991 | 4,572 | Fair |
| M-32 over Thunder Bay River | 1927 | 4,572 | Fair |
| Co Road 451 over N Br Thunder Bay River | 1994 | 2,126 | Fair |
| M-33 over Gilchrist Creek | 1951 | 1,647 | Fair |
| M-33 over Thunder Bay River | 1968 | 1,647 | Fair |
All bridges nearby: Montmorency County, MI bridge conditions · every bridge in Montmorency County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.