M-84 (Michigan highway)

M-84
M-84 highlighted in red
Route information
Maintained by MDOT
Length	14.710 mi[1] (23.673 km)
Existed	1960[2][3]–present
Major junctions
South end	M-58 in Saginaw
Major intersections	I-75 / US 23 near Bay City
North end	M-25 in Bay City
Location
Country	United States
State	Michigan
Counties	Saginaw, Bay
Highway system
Michigan State Trunkline Highway System Interstate US State Byways
← M-83 → M-85

M-84 is a north–south state trunkline highway in the Lower Peninsula of the US state of Michigan. The highway starts on the west side of Saginaw at an intersection with M-58 and runs north through residential and commercial areas. There are two colleges or universities near the trunkline as it connects Saginaw with Bay City, providing an alternative to the freeway that carries Interstate 75/US Highway 23 (I-75/US 23). The northern terminus is at a pair of intersections with M-25 on the east side of the Saginaw River in Bay City.

There have been two other highways to bear the M-84 moniker. The first was one in the Upper Peninsula and the second was in The Thumb area. The current highway was originally part of M-47 until that road was relocated onto what was formerly US 10 in the Tri-Cities area. Since the 1960s reuse of the number, M-84 has been extended in the 1970s to replace part of Business Loop I-75 (BL I-75, now Business Spur I-75, BS I-75) in Bay City. Other projects have reconstructed and widened the roadway through the Bay City area in the early 21st century.