The highway remained mostly unimproved for many years after designation by the state. The portion of highway from US 95 to Denio became a gravel road by 1940 and was not fully paved until 1953. The route was realigned near Denio Junction by 1949 (eliminating backtracking through Denio) and the portion between Denio and the California state line had been improved to a fully graveled road by 1952. 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. When Nevada officials began the process of renumbering the state's highways in 1976, SR 140 was planned to be redesignated as State Route 291. The proposed route number was first seen on the 1978 version of the state's highway map. Once the renumbering process was finished in the early 1980s, however, the highway retained the State Route 140 designation it has today. The route has remained relatively unchanged since. Major intersections See also Other segments of former State Route 8A: State Route 305, the central segment that ran from Austin to Battle Mountain. State Route 376, the southern segment that ran from near Tonopah to near Austin.