Plumas County is a county located in California's Sierra Nevada in the United States. The county gets its name from the Spanish words for the Feather River (Rio de las Plumas), which flows through the county. As of 2000, the population is 20,824. The county seat is Quincy. According to the U.S. Census Bureau, the county has a total area of 6,769 km² (2,613 mi²). 6,614 km² (2,554 mi²) of it is land and 155 km² (60 mi²) of it is water. The total area is 2.29% water. As of the census2 of 2000, there were 20,824 people, 9,000 households, and 6,047 families residing in the county. The population density was 3/km² (8/mi²). There were 13,386 housing units at an average density of 2/km² (5/mi²). The racial makeup of the county was 91.78% White, 0.62% Black or African American, 2.55% Native American, 0.53% Asian, 0.10% Pacific Islander, 1.81% from other races, and 2.61% from two or more races. 5.65% of the population were Hispanic or Latino of any race.