M-78 (Michigan highway)

M-78
M-78 highlighted in red
Route information
Maintained by MDOT
Length	10.744 mi[1] (17.291 km)
Existed	c. July 1, 1919[2]–present
Major junctions
West end	M-66 north of Battle Creek
East end	I-69 near Olivet
Location
Country	United States
State	Michigan
Counties	Calhoun, Barry, Eaton
Highway system
Michigan State Trunkline Highway System Interstate US State Byways
← M-77 → M-79

M-78 is a state trunkline highway in the US state of Michigan. The western terminus is the intersection with M-66 north of Battle Creek in Pennfield Township. The roadway runs 10.744 miles (17.291 km) through rural farmland and the community of Bellevue as it approaches its eastern terminus at an interchange with Interstate 69 (I-69) near Olivet. The highway is used by between 3,100 and 5,300 vehicles on a daily basis.

When the state highway system was signed in 1919, M-78 followed a similar routing. At Bellevue, it turned northeast to terminate at Charlotte. In the 1920s, the highway was extended southerly to the Indiana state line near Sturgis and northeasterly into the Lansing area. In the 1930s, M-78 was extended further on its northern and eastern end to Flint. The highway was converted into a freeway in sections starting in the 1960s. During that decade, the southern extension from the 1920s was removed from M-78 and added to other state highways, and in the 1970s, the northeastern extensions, now mostly freeways, were removed from M-78 as well. Two special routes were created as a result of the various reroutings in the Lansing area, both of which are no longer part of the state highway system.