High Quality Content by WIKIPEDIA articles! 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.