Lassen County, California

Lassen County
Interactive map of Lassen County
Location in the state of California
Coordinates: 40°42′55″N 120°37′16″W / 40.715287°N 120.621223°W / 40.715287; -120.621223
CountryUnited States
StateCalifornia
RegionShasta Cascade
Incorporated1 April 1864
Named afterPeter Lassen
County seatSusanville
Largest citySusanville
Government
 • TypeCouncil–CAO
 • BodyBoard of Supervisors
 • ChairGary Bridges
 • Vice ChairAaron Albaugh
 • Board of Supervisors
Supervisors
  • Mike Scanlan
  • Gary Bridges
  • Tom Neely
  • Aaron Albaugh
  • Jason Ingram
 • County Administrative OfficerSusan R Parker
Area
 • Total
4,720.115 sq mi (12,225.04 km2)
 • Land4,541.369 sq mi (11,762.09 km2)
 • Water178.746 sq mi (462.95 km2)
Highest elevation
8,741 ft (2,664 m)
Population
 (2020)
 • Total
32,730
 • Estimate 
(2024)
28,340
 • Density7.207/sq mi (2.783/km2)
GDP
 • Total$1.298 billion (2022)
Time zoneUTC−8 (Pacific Standard Time)
 • Summer (DST)UTC−7 (Pacific Daylight Time)
Area code530 and 837
Congressional district1st
Websitehttps://co.lassen.ca.us/

Lassen County (/ˈlæsən/ LASS-ən) is a county located in the northeastern portion of the U.S. state of California. As of the 2020 census, the population was 32,730, and was estimated to be 28,340 in 2024, Its county seat and the largest city is Susanville.

Lassen County comprises the Susanville, California micropolitan statistical area. A former farming, mining, and lumber area, its economy now depends on employment at one federal and two state prisons; the former in Herlong and the latter two in Susanville. In 2007, half the adults in Susanville worked in one of the facilities.