In the 1950s, a push began for an all-weather route connecting northwestern Nevada, southern Oregon, and the redwood region of California—at the time, there were no improved roads directly connecting these areas. Community leaders along the route formed an association to promote what they called the "Winnemucca to the Sea Highway". Efforts to realize the association's goals moved forward in the next decade. By 1960, Nevada officials had paved a portion of State Route 8A west of Denio. Instead of following SR 8A to Vya, the newly paved road curved northwest to the Oregon border near the Humboldt–Washoe county line. Oregon officials constructed a new paved road linking Adel to the Nevada state line in 1962. This work completed the stretch of Winnemucca to the Sea Highway between Denio Junction and Lakeview, Oregon. The Winnemucca to the Sea Association, however, envisioned Route 140 as a continuous number—branching from "parent" highway U.S. Route 40 in Winnemucca—that would be applied to the entire length of highway. By 1968, State Route 140 had been designated along the paved portions of SR 8A, with Oregon Route 140 continuing on to Adel and Lakeview. State Route 140 was also signed along US 95 south into Winnemucca—this section of SR 140 was later removed in the 1970s, around the same time as its "parent route" US 40 was decommissioned in Nevada.