M-21 over Maple River
Poor Condition97 years old2,533 vehicles/day
Location
| State | Michigan |
| County | Ionia |
| Location | 1.0 Mi E Of Muir |
| Carries | M-21 |
| Crosses | Maple River |
| Coordinates | 43.00073, -84.92144 |
Condition Ratings
| Overall Condition | Poor |
| Deck | 6 (Satisfactory) |
| Superstructure | 5 (Fair) |
| Substructure | 4 (Poor) |
| Channel/Waterway | 6 (Satisfactory) |
| Scour Critical | 3 — Scour critical |
Physical Characteristics
| Material | Steel |
| Design | Stringer/Multi-beam |
| Total Length | 220.1 ft (67.1 m) |
| Max Span | 53.8 ft (16.4 m) |
| Deck Width | 45.9 ft (14 m) |
| Deck Area | 939.4 sq m |
| Main Spans | 4 |
| Year Built | 1929 (reconstructed 2005) |
Traffic
| Avg Daily Traffic | 2,533 (2007) |
| Truck Traffic | 13% |
| Lanes On Bridge | 2 |
Inspection & Ownership
| Last Inspection | October 2024 |
| Inspection Frequency | Every 24 months |
| Owner | State Highway Agency |
| Historical Significance | Bridge is not eligible for the National Register |
| Structure Number | 000000000004011 |