State Route 140 is a two-lane state highway in Humboldt County, Nevada. It serves a sparsely populated section of the state, connecting northwestern Nevada to southern Oregon. Most of the highway was originally part of State Route 8A, and was later improved through an effort to provide an all-weather highway linking northern Nevada to the Pacific Northwest.

Humboldt County is a county in the U.S. state of Nevada. As of the 2020 Census, the population was 17,285. It is a largely rural county that is sparsely populated with the only major city being Winnemucca which has a population of 8,431. Humboldt County comprises the Winnemucca, NV Micropolitan Statistical Area and serves as an important crossroads in the national transportation network. Interstate 80 travels through the southeastern corner of the county, meeting US 95 in Winnemucca that serves as a primary freight corridor between Northern Nevada and Boise, Idaho and the Interstate 84 freight corridor that links much of the Pacific Northwest. The original transcontinental railway, constructed by the Central Pacific Railroad, reached Humboldt County on September 16, 1868. The Western Pacific Railroad would reach Humboldt County by November 1909, providing two mainline rail links to California and the Eastern United States. Both railroads have since been acquired by the Union Pacific Railroad, who continues to serve the region today.