A pathway connecting Panaca and Modena appears on state maps by 1927 as a county road. This route had been improved to a graded highway and designated State Route 25 by 1932. The entire route was paved by 1951. By 1933, State Route 25 was extended westward. It followed US 93/
State Route 7 south through
Caliente and west to
Crystal Springs, where it headed northwest towards
U.S. Route 6/
State Route 4 ending near
Tonopah. The western segment of route underwent numerous realignments over the next few several years, with the western terminus shifting eastward on US 6 to
Warm Springs by the time the highway was paved in 1958. Once paved, both parts of State Route 25 remained unchanged until July 1, 1976. On that date, Nevada authorized the
renumbering of all its state highways. During that process, the eastern section of SR 25 became the new State Route 319 while the western segment became
State Route 375. The changes were first noted on the 1978 edition of the official state highway map. ==Major intersections==