M-33 (Michigan highway)

M-33
M-33 highlighted in red
Route information
Maintained by MDOT
Length	121.858 mi[1] (196.111 km)
Existed	c. July 1, 1919[2]–present
Major junctions
South end	I-75 at Alger
Major intersections	M-55 near West Branch M-72 at Mio M-32 at Atlanta M-68 at Onaway
North end	M-27 near Cheboygan
Location
Country	United States
State	Michigan
Counties	Arenac, Ogemaw, Oscoda, Montmorency, Presque Isle, Cheboygan
Highway system
Michigan State Trunkline Highway System Interstate US State Byways
← US 33 → M-34

M-33 is a north–south state trunkline highway in the US state of Michigan that runs from Interstate 75 (I-75) at Alger in Arenac County north to M-27 near Cheboygan. In between, the trunkline runs through rural sections of the northeastern Lower Peninsula including state and national forest areas. M-33 connects to a handful of parks and crosses several of the rivers in that section of the state. It runs concurrently with three other state highways, sharing pavement to connect through several small communities of Northern Michigan.

M-33 was designated by 1919 along a section of the current highway between Mio and Atlanta. The highway also included roadway segments south of Mio that are now parts of other trunklines. The portion south of Mio was rerouted in the mid-1920s, transferring sections to M-72 in the process. The state started extending M-33 in both directions in the 1930s. The current highway segment between Onaway and Cheboygan was the former route of US Highway 23 (US 23) until 1940 when the latter highway was realigned onto an alignment that runs along Lake Huron. Several minor changes have been made to M-33's routing since the 1950s to straighten out curves or finish paving the highway.