 Montana State Highway 48 ( MT 48 ) is a short state maintained highway located in Deer Lodge County , in the southwestern region of the U.S. state of Montana . 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 . 
