According to the US Bureau of Justice Statistics' 2008 Census of State and Local Law Enforcement Agencies, California had 509 law enforcement agencies employing 79,431 sworn peace officers, about 217 for each 100,000 residents.
California peace officers' authority is derived from the California Penal Code (PC) beginning with Section 830. PC 830.1 includes California Department of Justice along with local and county agencies. PC 830.2 includes California Highway Patrol and nine (9) other state agencies. PC 830.3 includes 21 state agencies with law enforcement divisions.
State agencies
California Department of Justice
California Department of Justice Special agents
California Bureau of Investigation
California Bureau of Firearms
California Bureau of Forensic Services
California Bureau of Gambling Control
California Bureau of Medi-Cal Fraud & Elder Abuse
California Highway Patrol
California Department of Corrections and Rehabilitation
State Fugitive Apprehension Teams & Special Service Unit
California Department of Alcoholic Beverage Control
Department of Alcoholic Beverage Control
California Department of Alcoholic Beverage Control Agents Investigators
California Department of Alcoholic Beverage Control Task Forces Co-Operations
California Department of Fish and Wildlife
California State Parks Peace Officer
California Department of Toxic Substances Control
California Department of Motor Vehicles
The department was reduced to the Division of Motor Vehicles Investigations Division
California Department of Insurance Fraud Division
California Franchise Tax Board Criminal Investigations Bureau (CFTB-CIB)
California Lottery Security Law Enforcement Division
California Department of Consumer Affairs
California Department of Consumer Affairs
California Department of Consumer Affairs Division of Investigation
California Department of Health Care Services
California Department of Public Health
California Health and Human Services Agency
California Department of State Hospitals
California Department of State Hospitals Law Enforcement Office of Protective Services (California Department of State Hospitals Police)
California Department of Developmental Services
California Department of Developmental Services Police
California Employment Development Department Investigation Division
County agencies
Municipal agencies
College and University agencies
K-12 School Agencies
Apple Valley Unified School District Police Department
Baldwin Park Unified School District Police Department
Clovis Unified School District Police Department
Compton Unified School District Police Department
Elk Grove Unified School District Police Department
Fontana School District Police Department
Hesperia School District Police Department
Huntington Beach Union High School District Police Department
Inglewood Unified School District Police Department
Kern High School District Police Department
Los Angeles School Police Department
Long Beach Unified School District School Safety Department
Montebello Unified School District Police Department
Norwalk-La Mirada Unified School District School Safety Department
Oakland Unified School District Police Department
San Bernardino City Unified School District Police Department
San Diego City Schools Police Department
Santa Ana Unified School District Police Department
Stockton Unified School District Police Department
Twin Rivers Unified School District Police Department
Val Verde Unified School Police Department
Victor Valley Union High School District Police Department
West Contra Costa Unified School District Police Department
Special District agencies
Bay Area Rapid Transit Police Department
Bear River Police Department
Bear Valley Police Department (Bear Valley Community Services District)
Bethel Island Municipal Improvement District (BIMID)
Capistrano Bay Police Department (Capistrano Bay Community Services District)
Central Marin Police Authority
California Exposition & State Fair Police (Cal Expo Police)
East Bay Regional Park District Police Department
Exposition Park Department of Public Safety
Fulton–El Camino Park Police Department
Hoopa Valley Tribal Police Department
Kensington Police Protection and Community Services District
Kern County Airport Police
Lake Shastina Police Department (Lake Shastina C.S.D.)
Long Beach Harbor Patrol
Long Beach Park Rangers (Enveloped into the Long Beach Police Department, Disbandment proposed in late 2022)
Los Angeles World Airports Police Division
Los Angeles Department of Recreation and Parks, Park Ranger Division
Port of Los Angeles Police Division
Los Angeles Society for the Prevention of Cruelty to Animals Law Enforcement Division
Midpeninsula Regional Open Space District Ranger Division
Montebello Park Rangers
Monterey County Park Rangers
Monterey Peninsula Airport Police
Metropolitan Transit System Police Department
Napa Valley Railroad Police Department
Port of Stockton Police
Round Valley Tribal Police Department
Sacramento Regional Transit Police
San Diego Harbor Police (San Diego Unified Port District)
San Diego Humane Society and SPCA Law Enforcement / Investigations Division
San Francisco Park Patrol
Santa Ana Park Rangers
Santa Cruz Harbor Patrol
Stallion Springs Police
Town of Discovery Bay Community Services District (CSD)
Yurok Tribal Police Department
Federal law enforcement agencies in California
ATF
Bureau of Indian Affairs Police
Department of Defense Police
Defense Logistics Agency Police
Federal Bureau of Prisons
Federal Protective Service
Federal Reserve Police
Homeland Security Investigations
Immigration and Customs Enforcement
United States Fish and Wildlife Service
Office of the United States Marshal for the Northern District of California
Office of the United States Marshal for the Eastern District of California
Office of the United States Marshal for the Central District of California
Office of the United States Marshal for the Southern District of California
United States Coast Guard
United States Secret Service
United States Customs and Border Protection
United States Immigration and Customs Enforcement
United States Naval Criminal Investigative Service
United States Department of Veterans Affairs Police
United States Army Military Police Corps (Civilian/Uniformed)
United States Air Force Security Forces (Civilian/Uniformed)
United States Marine Corps Provost Marshall's Office ((Civilian/Uniformed))
Commander, Navy Region Southwest Police (Civilian/Uniformed)
United States Postal Service (Special Agents/OIG)
Defunct agencies
California State Police (merged with California Highway Patrol)
California State Rangers
Ex:
California State Parks Peace Officers
California Bureau of Narcotic Enforcement
Alviso Police Department merged into San Jose Police Department
Avalon Police Department Disbanded - services now provided by the Los Angeles Sheriff's Department
Blue Lake Police Department - merged with Humboldt County Sheriff's Department and partially replaced by Blue Lake Rancheria Police Department
Compton Police Department (disbanded in 2000)
Dorris Police Department Disbanded - Services contracted with Siskiyou County Sheriff's Office
Dunsmuir Police Department Disbanded - Services contracted with Siskiyou County Sheriff's Office
Ft. Jones Police Department Disbanded - Services provided by Etna Police Department
Grossmont-Cuyamaca Community College Police Department - Disbanded - Services provided by San Diego County Sheriff's Department
Half Moon Bay Police Department Disbanded - Services contracted with San Mateo County Sheriff's Office
Holtville Police Department Disbanded - Merged into Imperial County Sheriffs' Office
Housing Authority City of Los Angeles Police Department (disbanded on 12/31/03, area serviced by Los Angeles Police Department)
Imperial Beach Police Department Disbanded - Merged into San Diego County Sheriff's Department 1982
Isleton Police Department (Disbanded in 2012, area serviced by Sacramento County Sheriff's Department)
Los Angeles General Services Police now the Los Angeles Police Department (LAPD) Security Services Division
Los Angeles Community College District Police Department merged into LASD
Los Angeles County Office of Public Safety
Maricopa Police Department Disbanded - Merged into Kern County Sheriff's Office
Maywood-Cudahy Police Department
Millbrae Police Department Disbanded - Services contracted with San Mateo County Sheriff's Office
Montague Police Department Disbanded - Services provided by Siskiyou County Sheriff's Office
Santa Clara County Transit Police - Services contracted with the Santa Clara County Sheriff's Department Transit Patrol Division
San Anselmo Police Department
San Carlos Police Department Disbanded - Services contracted with San Mateo County Sheriff's Office
San Juan Bautista Police Department
San Jose Unified School District Police
Southern California Rapid Transit District Police Department
Stanton Police Department Disbanded - Merged into Orange County Sheriff's Department in February, 1988
Trinidad Police Department (Disbanded in 2010) merged with Humboldt County Sheriff's Department and partially replaced by Trinidad Rancheria Police Department
Twin Cities Police Authority now known as Central Marin Police Authority
Willows Police Department disbanded as of 7/1/17. Services provided by Glenn County Sheriff's Office