Humboldt River, river formed by the confluence of the East and North forks, Elko county, north-central Nevada, U.S. The headwaters of the Humboldt rise in the Ruby, Jarbidge, Independence, and East Humboldt mountain ranges in Humboldt National Forest. Flowing in a tortuous channel generally west and southwest past Elko, Winnemucca, and Lovelock, the Humboldt, after a course of about 300 miles (480 km), enters Humboldt Lake (also called Humboldt Sink), an intermittently dry lake bed with no outlet, near Humboldt Range. Named by the soldier-explorer John C. Frémont for Alexander von Humboldt, the German explorer and scientist, it provided an important route for the Emigrant Trail through Nevada, for emigrants traveling from Salt Lake City, Utah, to central California, especially after the discovery of gold there in 1848. After the completion of the transcontinental railroad in 1869, it became a major east-west rail route and is now the basis of Interstate 80. The Rye Patch Dam (1936, enlarged 1976), forming Rye Patch Reservoir, is located 26 miles (42 km) upstream from Lovelock, Nevada.