Bridge conditions in Ontonagon County, Michigan
66 inventoried bridges · 10 rated poor · 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
Ontonagon County has 10 bridges rated poor out of 66 inventoried, a 15.2% share that puts it well above the national rate of about 7%.
- 10 of the 66 bridges in Ontonagon County, Michigan, are rated in poor condition (15.2%) in the 2025 National Bridge Inventory, as of .
- 25 bridges (37.9%) are rated good and 31 (47.0%) fair.
- The median Ontonagon County bridge was built in 1968.
- The busiest poor-rated bridge is M-28 over Wapato Creek (built 1938), carrying about 1,845 vehicles a day.
Good 37.9% · Fair 47.0% · Poor 15.2% of 66 bridges
Bridges rated poor
Every bridge in the county with a poor rating, busiest first. Poor means a major component is rated 4 or lower on FHWA's 0-9 scale; it is a repair flag, not a closure notice.
| Bridge | Built | Vehicles/day | Condition |
|---|---|---|---|
| M-28 over Wapato Creek | 1938 | 1,845 | Poor |
| US-45 over Clear Creek | 1931 | 1,648 | Poor |
| M-64 over Pine River | 1968 | 1,032 | Poor |
| Old M-107 over Union River | 1976 | 831 | Poor |
| Old M-107 over Little Iron River | 1967 | 831 | Poor |
| Old M-107 over Big Iron River | 1938 | 831 | Poor |
| Bond Falls Road over Mid Br Ontonagon River | 1940 | 400 | Poor |
| Main St over Mineral River | 1955 | 250 | Poor |
| Lakeshore Drive over Firesteel River | 1976 | 120 | Poor |
| Gardner Road over E Branch Ontonogon River | 1954 | 100 | Poor |
Busiest bridges in the 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 |
| M-64 over Dreiss Creek | 1945 | 2,117 | Good |
| M-28 over Baltimore River | 1968 | 2,075 | Good |
| M-64 over Potato River | 1952 | 2,025 | Fair |
| M-28 over Wapato Creek | 1938 | 1,845 | Poor |
Source: FHWA National Bridge Inventory, 2025. Counts cover inventoried highway bridges over 20 feet; ratings are reported by the state DOT.
All of Michigan: Michigan bridge conditions by county · every download on the data page.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.