Mcmurphy Road over Thunder Bay River
Montmorency County, Michigan · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Mcmurphy Road over Thunder Bay River in Montmorency County, Michigan, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 7 (good condition) on the 0-9 scale.
- It was built in 2003, making it 22 years old at the 2025 inventory.
- It carries about 60 vehicles a day (traffic count year 2009).
- Its listed owner is the county highway agency.
- It is one of 13 of the 21 inventoried bridges in Montmorency County rated good (61.9%); 0 (0.0%) 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 → (44.97419, -84.09359)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 7 | Good condition |
Bridge details
| Structure | Concrete culvert |
| Length | about 44 ft |
| Location | Sections 20-21 Avery Twp |
| NBI structure number | 000000000012717 |
| Condition class | Good |
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.