Business M-28 was a state trunkline highway in the Upper Peninsula of Michigan. It served as a business route running for 9.010 miles (14.500 km) through the Newberry area. The business loop followed a U-shaped routing to connect downtown Newberry with M-28 south of town. It ran west of the city of Newberry, passing through the community of Dollarville before entering downtown, turning south and ending near the county airport.

M-28 is an east–west state trunkline highway that traverses nearly all of the Upper Peninsula of the U.S. state of Michigan, from Wakefield to near Sault Ste. Marie in Bruce Township. Along with US Highway 2 (US 2), M-28 forms a pair of primary highways linking the Upper Peninsula from end to end, providing a major access route for traffic from Michigan and Canada along the southern shore of Lake Superior. M-28 is the longest state trunkline in Michigan numbered with the "M-" prefix at 290.373 miles (467.310 km). The entire highway is listed on the National Highway System, while three sections of M-28 are part of the Lake Superior Circle Tour. M-28 also carries two memorial highway designations along its route.