Lassen County is a county located in northeastern California. As of 2000 the population was 33,828. The county seat is Susanville, the only incorporated city in the county. Lassen County was formed in 1864 from parts of Plumas and Shasta Counties. Due to uncertainties over the California border, what is now Lassen County was part of the unofficial Nataqua Territory and Roop County, Nevada during the late 1850s and early 1860s. As of the census2 of 2000, there were 33,828 people, 9,625 households, and 6,776 families residing in the county. The population density was 3/km² (7/mi²). There were 12,000 housing units at an average density of 1/km² (3/mi²). The racial makeup of the county was 80.81% White, 8.84% Black or African American, 3.26% Native American, 0.74% Asian, 0.43% Pacific Islander, 3.23% from other races, and 2.69% from two or more races. 13.84% of the population were Hispanic or Latino of any race.