Thumb Lake Road over N Br Boyne River
Charlevoix County, Michigan · rated Good in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Thumb Lake Road over N Br Boyne River in Charlevoix County, Michigan, is rated in good condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the culvert, rated 8 (very good condition) on the 0-9 scale.
- It was built in 2003, making it 22 years old at the 2025 inventory.
- It carries about 2,545 vehicles a day (traffic count year 2003).
- Its listed owner is the county highway agency.
- It is one of 7 of the 18 inventoried bridges in Charlevoix County rated good (38.9%); 2 (11.1%) 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 → (45.17516, -84.8985)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Culvert | 8 | Very good condition |
Bridge details
| Structure | Steel culvert |
| Length | about 23 ft |
| Location | 0.7 Mi E of Boyne Falls |
| NBI structure number | 000000000013739 |
| Condition class | Good |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
Busiest bridges in Charlevoix County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| US-31 over Pine River | 1949 | 15,321 | Fair |
| US-131 over Boyne River | 1947 | 6,736 | Fair |
| M-75|s East St over Boyne River | 1974 | 6,546 | Fair |
| Park Street over Boyne River | 1991 | 5,000 | Fair |
| M-32|water St over S Arm Lake Charlevoix | 1959 | 4,600 | Fair |
| Lake Street over Boyne River | 1959 | 3,000 | Fair |
All bridges nearby: Charlevoix County, MI bridge conditions · every bridge in Charlevoix County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.