M-55 (Michigan highway)

M-55
M-55 highlighted in red
Route information
Maintained by MDOT
Length	150.944 mi[1] (242.921 km)
Existed	c. July 1, 1919–present
Major junctions
West end	US 31 near Manistee
Major intersections	M-37 near Dublin US 131 at Cadillac US 127 near Houghton Lake I-75 near Prudenville M-33 near West Branch M-65 near Whittemore
East end	US 23 in Tawas City
Location
Country	United States
State	Michigan
Counties	Manistee, Wexford, Missaukee, Roscommon, Ogemaw, Iosco
Highway system
Michigan State Trunkline Highway System Interstate US State Byways
← M-54 → M-56

M-55 is a state trunkline highway in the northern part of the US state of Michigan. M-55 is one of only three state highways that extend across the Lower Peninsula from Lake Huron to Lake Michigan; the others are M-46 and M-72. The highway crosses through rural forest and farmlands to connect Manistee with Tawas City. M-55 crosses two of the major rivers in the state. Two sections of the highway follow along freeways near Cadillac and West Branch. Running for 150.944 miles (242.921 km) through the state, M-55 is maintained by the Michigan Department of Transportation (MDOT).

The highway was first designated by July 1, 1919 along a portion of the current roadway. In a series of extensions, M-55 was lengthened to connect its current endpoints by the early 1930s. The trunkline has been rerouted in sections since that time resulting in the modern roadway alignment. One set of changes produced a business loop in the Houghton Lake area.