A county road approximating the course of the present highway was indicated on state maps by 1933. As of 1935, State Route 38 was designated along the north end of the county road, between State Route 4 (later US 6) at Barnes and the town of Lund. This segment of highway was completely paved by 1936. The remaining unimproved portions of the county road was made part of the state highway system by 1937—the from US 93 to Hiko became the first iteration of SR 60, while the remaining was designated SR 38A. By 1939, however, SR 60 was removed and replaced by SR 38A—the southern end of the route was also shifted more easterly by this time. In 1942, the entire length of SR 38A between US 93 and Lund had been graded to more closely follow the White River. The SR 38A designation was completely absorbed into SR 38 by 1946—by this time, SR 38 was approximately long.