M-40 (Michigan highway)

M-40
M-40 highlighted in red
Route information
Maintained by MDOT
Length	74.266 mi[1] (119.520 km)
Existed	c. July 1, 1919[2]–present
Major junctions
South end	US 12 in Porter Township
Major intersections	M-60 in Newberg Township M-216 in Marcellus I-94 near Paw Paw M-43 near Gobles M-89 in Allegan I-196 in Holland
North end	BL I-196 / US 31 in Holland
Location
Country	United States
State	Michigan
Counties	Cass, Van Buren, Allegan
Highway system
Michigan State Trunkline Highway System Interstate US State Byways
← M-39 → US 41

M-40 is a north–south state trunkline highway in the Lower Peninsula of the US state of Michigan. The highway runs from US Highway 12 (US 12) near the Indiana state line in Porter Township north through Paw Paw and Allegan to end in the outskirts of Holland. The current northern end is near Interstate 196 (I-196) at an intersection with US 31/Business Loop I-196 (BL 196). In between, M-40 runs through mixed agricultural and forest lands and along lakes and rivers through Southwest Michigan.

The trunkline was designated by July 1, 1919, along with the rest of the original state highway system along a route that is different that of that of the 21st century. South of Paw Paw, the original M-40 reached Niles and even the Indiana state line for a time. The northern end was extended in stages to Holland. The southern end was shifted in the 1970s, resulting in the modern routing.