Beckwourth is a census-designated place (CDP) in Plumas County, California, United States. The population was 342 at the 2000 census. According to the USGS National Geographic Names Database, a variant spelling was Beckwith and its name comes from an early explorer who had changed his name from Beckwith to Beckwourth: Named for James P. Beckwourth (d.1867), adventurer, trapper, and trail blazer who discovered Beckwourth Pass in 1851. Beckwourth built the first house in the Sierra Valley where he operated an inn and trading post. During the 1850's, Beckwourth Pass was the portal of an immigrant route into California through Lassen, Plumas, Butte and Yuba counties known as the Beckwourth Trail.