COUNTY · CA
Lassen County, California
Lassen County is a county in California with FIPS code 06035 and an estimated population of 28,861 (Census 2023), 47th largest of 58 in the state.
County facts
- Name
- Lassen County
- State
- California
- Type
- county
- FIPS code
- 06035
- State FIPS
- 06
- Population (2023)
- 28,861
- Change since 2020
- -10.7%
- State rank
- 47 of 58
Population is the Census Bureau’s Vintage 2023 estimate.
Questions
What is the FIPS code for Lassen County?
Lassen County, California has the five-digit FIPS code 06035: 06 for the state and 035 for the county.
What state is Lassen County in?
Lassen County is in California.
How do I know if an address is in this county?
Use the address lookup. ZIP codes and city names can cross county lines, so an address is the reliable check.
Sources: U.S. Census Bureau geographic reference files; Census Bureau Population Estimates, Vintage 2023. Last reviewed 2026-10-27.