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 today. 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 current routing. Route description M-40 starts at an intersection with US 12 in rural Cass County. Running north through farm fields, the highway rounds Bar Lake and into the community of Jones. The area around Jones has a few more lakes in a wooded setting. As the trunkline continues north, it passes back into farm lands. The road curves around to the northwest as it passes between Bogart Lake and Streeters Mill Pond near Dutch Settlement Road. M-40 follows Centre Street into Marcellus. When the highway meets the western end of M-216 in town, M-40 turns west along Main Street and runs out of town. The roadway returns to a northerly course, and later it curves northwesterly again near Cedar Lake near the Van Buren County line. Continuing north, the trunkline passes through mixed agricultural and wood lands into the community of Lawton. M-40 follows Main Street through town and exits on a northwestern track towards the village of Paw Paw. M-40 crosses over I-94 and turns north into town running along Maple Lake. The highway crosses the narrow isthmus between the larger Maple Lake and the smaller Ackley Lake, passing through some small residential subdivisions as it leaves Paw Paw. Small farms dot the landscape as M-40 crosses M-43 in a rural area of the county on the way to Gobles. It is in this small city that the road crosses the Kal-Haven Trail State Park, a linear park that follows the former Kalamazoo and South Haven Railroad line. The