| M-123 | ||||
|---|---|---|---|---|
| 
 M-123 highlighted in red 
 | 
||||
| Route information | ||||
| Maintained by MDOT | ||||
| Length: | 96.071 mi (154.611 km) | |||
| Existed: | 1936 – present | |||
| Tourist routes:  | 
 | 
|||
| Major junctions | ||||
| South end: | 
 | 
|||
| 
 
  | 
||||
| North end: | 
 | 
|||
| Location | ||||
| Counties: | Mackinac, Chippewa, Luce | |||
| Highway system | ||||
  | 
||||
H-40 in Trout Lake
M-28 near Eckerman
M-123 is a state trunkline highway in the eastern Upper Peninsula of the U.S. state of Michigan. It is one of only a few highways in Michigan that curve around and form a U-shape. In fact, M-123 has three intersections with only two state trunklines. It meets M-28 twice as a result of its U-shaped routing. M-123 also has a rare signed concurrency with a County-Designated Highway in Michigan; in Trout Lake, there is a concurrency with H-40. All of M-123 north of M-28 is a Scenic Heritage Route within the Michigan Heritage Route system.