By 1951 , the highway had been reconstructed generally along MT 87 's present location , and it had been upgraded to an improved gravel road . In 1959 , the road in the location of MT 87 was rapidly improved in order to serve as an alternate routing to U.S. Route 287 . Portions of US 287 around Hebgen Lake collapsed and crumbled as a result of the 1959 Hebgen Lake earthquake . After US 287 was fixed , the highway 's importance decreased . In 1962 , the portions of the highway from the southern terminus to present-day milepost 8.395 were reconstructed along the current location . In 1967 , the rest of the highway was reconstructed along the present location . By 1987 , the highway had been numbered as MT 87 . The route had also been paved
1959 Hebgen Lake earthquake
1959 Hebgen Lake earthquake
Montana Highway 87