M-42 is a rural state trunkline highway in the U.S. state of Michigan. It is located in the northwestern Lower Peninsula of the state. Along its route, M-42 begins in Manton and ends north of Lake City, some 10.356 miles (16.666 km) apart. The highway used to run much farther. Former termini included the Traverse City area from 1919 until 1940 and Mesick from 1940 until 2007.

Manton is a city in Wexford County in the U.S. state of Michigan. The population was 1,258 at the 2020 census. The city is located in northeastern Wexford County, which itself is part of Northern Michigan.