M-21 over North Swargart Drain
Clinton County, Michigan · rated Poor in the 2025 National Bridge Inventory
United States Bridge Conditions2025 National Bridge Inventory, FHWACompiled
- M-21 over North Swargart Drain in Clinton County, Michigan, is rated in poor condition in the 2025 National Bridge Inventory (as of ).
- It was built in 1977, making it 48 years old at the 2025 inventory.
- It carries about 4,192 vehicles a day (traffic count year 2007).
- Its listed owner is the state highway agency.
- A poor rating means at least one major component - deck, superstructure, or substructure - is rated 4 or lower on FHWA's 0-9 scale. It does not by itself mean the bridge is unsafe; bridges judged unsafe are closed or load-restricted by their owners.
View this bridge on a map → (43.0017, -84.67506)
Component ratings
| Component | Rating (2025) | FHWA scale meaning |
|---|---|---|
| Deck | 3 | Serious condition |
| Superstructure | 6 | Satisfactory condition |
| Substructure | 6 | Satisfactory condition |
Bridge details
| Structure | Prestressed concrete multiple box beam |
| Length | about 30 ft |
| Location | 3.2 Mi E of Fowler |
| NBI structure number | 000000000001882 |
Source: FHWA National Bridge Inventory, 2025 data as reported by the Michigan department of transportation.
All bridges nearby: Clinton County, MI bridge conditions · Michigan bridges.
Background: how bridge ratings work · what "poor" and "structurally deficient" actually mean · how often bridges are inspected.