Montana State Highway 48 (MT 48) is a 6.839-mile (11.006 km) state highway in Deer Lodge County, Montana, United States. The highway is 6.839 miles (11.006 km) long, and connects MT 1 to Interstate 90, passing mainly through rural mining areas. MT 48 was first designated in 1938, although portions of a highway existed in the location of MT 48 by at least 1924.