High Quality Content by WIKIPEDIA articles! M-75 is a 11.768-mile (18.939 km) segment of state trunkline highway located in Charlevoix County in the U.S. state of Michigan. This highway serves as a loop off US Highway 131 (US 131), providing access to Boyne City. The highway happens to be geographically close to Interstate 75 (I-75), but they are not related.