M-25 over Pinnebog River
Huron County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- M-25 over Pinnebog River in Huron County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the superstructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1976, making it 49 years old at the 2025 inventory.
- It carries about 1,500 vehicles a day (traffic count year 2011).
- Its listed owner is the state highway agency.
- It is one of 116 of the 192 inventoried bridges in Huron County rated fair (60.4%); 14 (7.3%) 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 July 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 → (43.99341, -83.07563)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 6 | 6 | Satisfactory condition |
| Substructure | 7 | 7 | Good condition |
Bridge details
| Structure | Prestressed concrete multiple box beam |
| Length | about 120 ft |
| Location | 6.0 Mi SW of Port Austin |
| NBI structure number | 000000000003450 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | July 2023 |
| 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 Michigan department of transportation.
Busiest bridges in Huron County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Anton Street over Sebewaing River | 2013 | 5,590 | Good |
| M-142 over Pinnebog River | 1946 | 5,274 | Good |
| M-142|pigeon Rd over Nettle Run | 2012 | 5,200 | Good |
| M-25 over Sebewaing River | 1949 | 5,123 | Fair |
| Center Street over Sebewaing River | 2003 | 4,900 | Fair |
| M-25 over Pigeon River | 1929 | 4,865 | Good |
All bridges nearby: Huron County, MI bridge conditions · every bridge in Huron County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.