M-25 (Michigan highway)

M-25
M-25 highlighted in red
Route information
Maintained by MDOT
Length	147.638 mi[1] (237.600 km)
Existed	1933[2][3]–present
Tourist routes	Lake Huron Circle Tour Center Avenue Heritage Route
Major junctions
South end	BL I-69 / BL I-94 at Port Huron
Major intersections	M-90 at Lexington M-46 at Port Sanilac M-142 at Harbor Beach M-53 at Port Austin M-142 at Bay Port M-24 at Unionville M-15 near Bay City
West end	I-75 / BS I-75 / US 10 / US 23 at Bay City
Location
Country	United States
State	Michigan
Counties	St. Clair, Sanilac, Huron, Tuscola, Bay
Highway system
Michigan State Trunkline Highway System Interstate US State Byways
← US 25 → M-26

M-25 is a state trunkline highway in the US state of Michigan. The route follows an arc-like shape closely along the Lake Huron shore of the Thumb in the eastern Lower Peninsula between Port Huron and Bay City. It serves the lakeshore resorts along Lake Huron and Saginaw Bay and generally lies within sight of the lake and the bay. All is surface road and generally scenic, except for the freeway segment near the junction with Interstate 75 (I-75) and connection into the US Highway 10 (US 10) freeway.

Between Port Huron and Port Austin it is the north–south highway was formerly US 25 before the designation was removed. Between Port Austin and Bay City it is an east–west route that appeared on some maps as US 25 and on some maps as M-25. Since the 1970s, when all of US 25 was deleted north of Cincinnati, Ohio, it is entirely signed as M-25.