Coonhill Road over Portage River Drain
Jackson County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Coonhill Road over Portage River Drain in Jackson 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 1975, making it 50 years old at the 2025 inventory.
- It carries about 900 vehicles a day (traffic count year 2003).
- Its listed owner is the county highway agency.
- It is one of 87 of the 158 inventoried bridges in Jackson County rated fair (55.1%); 17 (10.8%) 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 May 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 → (42.36453, -84.25788)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 5 | 5 | Fair condition |
| Superstructure | 5 | 5 | Fair condition |
| Substructure | 5 | 5 | Fair condition |
Bridge details
| Structure | Timber slab |
| Length | about 51 ft |
| Location | 2 Mi South of Munith |
| NBI structure number | 000000000004484 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | May 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 Jackson County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| Elm Rd over I-94 | 2022 | 54,000 | Good |
| Airport Rd over I-94 | 1958 | 46,000 | Fair |
| Whipple Rd over I-94 | 1960 | 38,000 | Fair |
| Sandstone Rd over I-94 | 1958 | 34,000 | Fair |
| I-94 EB over Jail RR & Grand River | 2019 | 33,550 | Good |
| I-94 WB over Jail RR & Grand River | 2020 | 33,550 | Good |
All bridges nearby: Jackson County, MI bridge conditions · every bridge in Jackson County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.