M-21 over Maple River
FairClinton County, Michigan · 2.0 MI W of Ovid · Structure no. 000000000001889
- Built
- 1929
- 96 years old, rebuilt 2004
- Condition
- Fair
- inspected October 2024
- Type
- Stringer/Multi-beam or Girder
- Prestressed Concrete
- Length
- 39 ft
- 1 main span
- Daily traffic
- 7,103
- 2007 count
- Owner
- State
- State Highway Agency
About this bridge
M-21 over Maple River is a prestressed concrete stringer/multi-beam or girder carrying M-21 over Maple River in Clinton County, Michigan. It was built in 1929 and reconstructed in 2004, so it is 96 years old, older than the Michigan average of 48.3 years.
The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
It carries about 7,103 vehicles a day, roughly 6% of them trucks, projected to reach 8,615 by 2018. The structure is 39 ft (11.9 m) long and 47 ft wide. If it were closed, the detour would be 3.1 mi (5 km).
Location
Open in Google MapsCondition and inspection
The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.
| Component | Rating | Meaning |
|---|---|---|
| Deck | 7 Good | Some minor problems. |
| Superstructure | 7 Good | Some minor problems. |
| Substructure | 6 Satisfactory | Structural elements show some minor deterioration. |
| Channel and channel protection | 6 Satisfactory | Structural elements show some minor deterioration. |
Structure
Traffic and service
Ownership and planned work
Frequently asked questions
When was M-21 over Maple River built?
It was built in 1929, making it 96 years old in 2025. It was reconstructed in 2004.
What condition is M-21 over Maple River in?
The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in October 2024.
How much traffic does M-21 over Maple River carry?
About 7,103 vehicles per day (2007 count), of which roughly 6% are trucks.
How long is M-21 over Maple River?
The structure is 39 ft (11.9 m) long with a longest span of 37 ft (11.4 m) and a deck 47 ft wide.
Who owns M-21 over Maple River?
It is owned by the State Highway Agency.