Forest Road 360 over Iron River
Ontonagon County, Michigan · rated Fair in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- Forest Road 360 over Iron River in Ontonagon County, Michigan, is rated in fair condition in the 2025 National Bridge Inventory (as of ).
- Its lowest-rated component is the substructure, rated 6 (satisfactory condition) on the 0-9 scale.
- It was built in 1972 and reconstructed in 1984, making it 53 years old at the 2025 inventory.
- It carries about 50 vehicles a day.
- It is one of 31 of the 66 inventoried bridges in Ontonagon County rated fair (47.0%); 10 (15.2%) 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 September 2024, 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 → (46.67835, -89.65138)
Component ratings
| Component | Rating (2024) | Rating (2025) | FHWA scale meaning |
|---|---|---|---|
| Deck | 7 | 7 | Good condition |
| Superstructure | 7 | 7 | Good condition |
| Substructure | 6 | 6 | Satisfactory condition |
Bridge details
| Structure | Steel stringer or multi-beam girder |
| Length | about 84 ft |
| Location | 6 Mi N 4 Mi W of Bergland |
| NBI structure number | 090701000001021 |
| Condition class | Fair |
| Traffic status (item 41) | Open, no restriction |
| Last inspection (item 90) | September 2024 |
| 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 Ontonagon County
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| M-64 & M-38 over Ontonagon R River Rd RR | 2005 | 3,625 | Fair |
| M-28 over So Br Ontonagon River | 1990 | 2,398 | Good |
| M-28 over M Br Ontonagon River | 1929 | 2,303 | Fair |
| M-28|m-64 over Merryweather Creek | 1932 | 2,120 | Fair |
| M-64 over Cranberry River | 1948 | 2,117 | Fair |
| M-64 over Weigels Creek | 1945 | 2,117 | Fair |
All bridges nearby: Ontonagon County, MI bridge conditions · every bridge in Ontonagon County · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.