 M-72 was first designated by July 1, 1919, and it ran from the middle of Alcona County near Barton City east to Harrisville and then south along Lake Huron shore to Greenbush.Around 1927, the route was extended south to Oscoda and west through Luzerne to just east of Roscommon.The section of M-72 along the shoreline between Oscoda and Harrisville became part of US 23. in 1936.