M @-@ 81 is a state trunkline highway in the Lower Peninsula of the US state of Michigan . The trunkline travel from the city of Saginaw at the junction with M @-@ 13 to the junction with M @-@ 53 east of Cass City over the county line in Greenleaf Township in northwestern Sanilac County in The Thumb area of the state . Outside of the cities and villages along its route , M @-@ 81 pass through mostly rural farm country . Near Saginaw it intersect the freeway that carry both Interstate 75 ( I @-@ 75 ) and US Highway 23 ( US 23 ) in an industrial area .