Sierra County

County in California

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Report created October 27, 2026 at www.firezones.info/county/091/sierra

  • Fire hazard severity zones

    Share of the land in each CAL FIRE hazard class

    20% Very High

    Most of the Very High land is in the State Responsibility Area, where the State Fire Marshal's zones apply.

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  • Fire history

    Share of the land inside a recorded wildfire perimeter

    31% has burned

    Most recently the 2025 Grove Fire, which burned 2 acres here, one of 193 fires on record.

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  • Power line fire risk

    Share of the land in the High Fire-Threat District

    15% Extreme

    Utilities may shut off power in the CPUC High Fire-Threat District in fire weather, and homes outside it can lose power when their lines run through it.

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Land by hazard class

  1. Very High 121,380 acres · 120,991 state, 389 local 20%
  2. High 32,647 acres · 31,703 state, 944 local 5%
  3. Moderate 4,516 acres · 3,972 state, 544 local 1%
  4. Non-wildland 23,712 acres · Local Responsibility Area 4%
  5. Not mapped by CAL FIRE 433,280 acres · Mostly federal land 70%

615,534 acres of land in all, 156,665 in the State Responsibility Area and 25,590 in the Local. State zones are the ones the State Fire Marshal designated, in effect since 1 April 2024. Local zones are CAL FIRE's 2025 recommendation, which each city or county adopts by ordinance and can make stricter. How to read fire zones

Largest fires

  1. 1994 Cottonwood Fire Cause: Arson 48,054 acres
  2. 1960 Donner Ridge Fire Of 43,374 acres in all · Cause: Debris burning 24,166 acres
  3. 2020 Loyalton Fire Of 46,721 acres in all · Cause: Lightning 23,559 acres
  4. 1959 Unnamed fire Of 18,522 acres in all · Cause: Miscellaneous 15,238 acres
  5. 1959 Unnamed fire Cause: Miscellaneous 11,427 acres
  6. 1987 Indian Fire Cause: Lightning 9,242 acres
  7. 1924 Unnamed fire Of 14,671 acres in all · Cause: Miscellaneous 9,076 acres
  8. 1954 Unnamed fire Cause: Campfire 7,586 acres
  9. 1994 Crystal Fire Cause: Equipment use 7,356 acres
  10. 1960 Unnamed fire Cause: Lightning 4,498 acres

And 183 smaller fires. In all, 189,127 acres of Sierra County have burned. Acres are the land each fire burned here, and fires that crossed less than an acre are not counted. Some older or smaller fires may be missing, and a fire perimeter can include unburned patches. How to read fire history

Sources

Fire hazard severity zones
CAL FIRE Office of the State Fire Marshal
State map published 27 June 2025, local map 2 February 2026
Fire history
CAL FIRE Fire and Resource Assessment Program
Published 28 July 2026
Power line fire risk
California Public Utilities Commission
Published 23 February 2026

This site is independent and not affiliated with CAL FIRE or the CPUC, so for an official determination, check with the agency or your city or county. How we read the data

Nearby areas

Cities and towns in Sierra County

Unincorporated communities in Sierra County

ZIP codes in Sierra County

Neighboring counties

  1. Sierra County 20% Very High · this area
  2. Lassen County 14% Very High
  3. Nevada County 52% Very High
  4. Plumas County 21% Very High
  5. Yuba County 29% Very High