Montana Highway 87 (MT 87) is a primary state highway in Madison County in Montana, United States. The highway travels through mainly rural areas in Raynolds Pass, from the Montana-Idaho state line to an intersection with U.S. Route 287 (US 287). The route travels through a portion of Gallatin National Forest. In 1922, a road in the location of MT 87 was added to the highway system, and a few years later the road was designated as portions of two early auto trails. In 1959, the route was rapidly improved due to the collapse of US 287 nearby. During 1967, much of the highway was reconstructed along its current location.