In the late 1930s, a highway numbered M-178 was designated between M-28 south of Munising to M-94 in town. In 1941, the routings of M-28 and M-94 were reversed between Harvey and Munising, and M-28 supplanted the M-178 designation completely. Since then, M-28 has run along the lakeshore through Au Train. M-28 was extended along US 2 to the state line at Ironwood, and the eastern end of M-28 through Brimley was moved to a new alignment ending at US 2, in Dafter in 1942. The eastern end was moved along US 2 back to Sault Ste. Marie in 1948, though the terminus was returned to Dafter in 1950.