 Eastern portions of the road in Brewster County, however, had several previous highway designations going back to 1939.In addition to SH 118 in Study Butte, FM 170 has highway intersections in Presidio with U.S. Route 67 and its auxiliary route Business U.S. Route 67-A along with State Highway Spur 203.The earliest portion of the present route to be designated as part of the state highway system was the section between Terlingua and Study Butte which was assigned in September 1939 as part of a spur to SH 227.