 M @-@ 103 is a state trunkline highway entirely within St. Joseph County in the southwestern region of the U.S. state of Michigan . The trunkline runs between U.S. Highway 12 ( US 12 ) in Mottville and the Indiana state line along undivided highway near the St. Joseph River . With the connection to State Road 15 ( SR 15 ) , it is part of the Great Lakes Circle Tour , a scenic byway tour of the Great Lakes region of the United States.
The route was assigned in 1919 from US 12 to Benton Harbor . In 1926, the route was extended south to the Indiana