Numerous police and international intelligence agencies classify the Hells Angels Motorcycle Club as a motorcycle gang and contend that members carry out widespread violent crimes, including drug dealing, trafficking in stolen goods, gunrunning, extortion, and prostitution rings. Members of the organization have continuously asserted that they are only a group of motorcycle enthusiasts who have joined to ride motorcycles together, to organize social events such as group road trips, fundraisers, parties, and motorcycle rallies, and that any crimes are the responsibility of the individuals who carried them out and not the club as a whole.

There are more Hells Angels chapters in California than in any other U.S. state. With over 300 members statewide, the Hells Angels are the most significant motorcycle gang in California in terms of membership and criminal activity. The club has a significant role in the manufacture and distribution of methamphetamine, and in other illegal enterprises.California Northern and Eastern Districts Drug Threat Assessment National Drug Intelligence Center, justice.gov (January 2001) The West Coast faction of the HAMC has also been especially active in the infiltration of legitimate businesses, including motorcycle and automobile services, catering operations, bars, restaurants, and antique stores.Organized Crime In California John K. Van De Kamp, California Department of Justice (1986) The San Fernando Valley chapter has colluded with the Los Angeles crime family and Five Families of New York in debt collection and the theft of electronics, and the San Jose charter has been linked with the San Jose crime family.Les Gangs de Motards Criminalisés: Une expansion internationale Xavier Raufer, Institut de Criminologie de Paris Additionally, the California Hells Angels have associated in criminal ventures with the Aryan Brotherhood,Hell’s Angels: Masters of Menace Howard Kohn, Rolling Stone (April 5, 1979) the Mexican Mafia, and the Nazi Lowriders.White Power Gangs: The NLR (Nazi Low Riders) Story B. Belt and G. Doyle, National Criminal Justice Reference Service (March 1998) A 1990 review by the California Department of Justice determined that the 215 members of fourteen Hells Angels chapters in the state had been arrested an average of 10.4 times each, in a total of 2,202 charges – most commonly, narcotics violations, assault, weapons violations, burglary and robbery. The offenders' crimes generally escalated after they gained membership of the club.Outlaw motorcycle gangs – USA overview National Institute of Justice (1991)

Early incidents Shortly after the foundation of the Hells Angels' North Sacramento chapter in 1956, twelve club members were arrested at a house party in Sacramento's Ben Ali neighborhood. After being elected sheriff of Sacramento County in January 1961, John Misterly began a campaign of surveillance and purported harassment against the Hells Angels. In 1964, one Hells Angel, Ernest Cannada, appeared before the Sacramento City Council and read a letter protesting alleged illegal tactics against the club by sheriff's deputies. During this period, Hells Angels members would reportedly remove their "colors" before entering Sacramento County due to Misterly's hostility towards the club. In the spring of 1965, James "Mother" Miles, the founding president of the Sacramento Hells Angels, disbanded the chapter and relocated it to Richmond, where its members joined forces with Hells Angels from the San Francisco Bay Area to form a Nomads chapter. Misterly took credit for ousting the Angels from the county and denied that his deputies were guilty of harassing the bikers. Misterly's supporters told The Sacramento Bee that his "harassment techniques" were "instrumental in the breakup of the Hells Angels", however.Driving out the Angels: How an outlaw motorcycle club was ousted from Sacramento Michael Anthony Adams, ABC 10 (August 5, 2017) Misterly allowed the Hells Angels to return to Sacramento as part of a one-day truce to attend the funeral of Miles, who was killed in a motorcycle accident in Berkeley on January 9, 1966. Up to 300 Hells Angels from eleven club chapters throughout California were present at Miles' funeral before they were given a police escort out of the city. The Sacramento chapter was re-established in 1973.

A group of Hells Angels armed with can-openers fought with United States First Fleet sailors on shore leave from the USS Bon Homme Richard, at a San Pablo drive-in theater on June 15, 1957. Police arrested seven people—four Hells Angels and three sailors. Two of the Hells Angels—Donald L. Reeves and Curis A. Hammond—were charged with disturbing the peace after trying to run down a San Pablo police sergeant while escaping the scene in a car. The pair were later arrested by Albany police. Additionally, James R. Jenkins, who was found in possession of a 15-inch length of chain, was charged with assault with a deadly weapon, and Norman C. Phillips, a California Youth Authority parolee, was charged with parole violation.Sailors, Cyclists In Fight Appeal-Democrat (June 15, 1957)

On January 29, 1963, the Hells Angels' Oakland headquarters was raided by police, and seven club members were charged with the alleged gang rape of a 29-year-old woman, which took place on January 27. Other charges included Hitlerism, marijuana possession and theft. A swastika flag and a picture of Adolf Hitler, with the inscription "Hitler is alive, our buddy", were also found on the premises.Vintage photos of Bay Area Hells Angels Motorcycle Club Bob Bragman, San Francisco Chronicle (February 3, 2017)

Five people were charged with inciting a riot and one with the illegal possession of a weapon after the Tulare County Sheriff's Department, the California Highway Patrol and local police dispersed approximately 200 members of seven motorcycle clubs from across California, including the Hells Angels and the Galloping Goose, who converged in Porterville on August 31 and September 1, 1963.It was a 'Hell's' of a day Rick Elkins, Porterville Recorder (September 2, 2013) Among numerous incidents of violence, a group of bikers allegedly stormed Sierra View District Hospital in an attempt to continue a fight with G.E. Montgomery, a resident of the city who was receiving medical treatment after earlier being beaten at a local tavern.Fire Hoses Disperse Porterville 'Cycle Mob The Fresno Bee (September 2, 1963) Hells Angels ride in Porterville Jeff Edwards, Porterville Recorder (June 7, 2000)

48 Hells Angels members and their girlfriends were arrested at their clubhouse on San Francisco's Folsom Street on December 5, 1964, on charges of robbery, assault with a deadly weapon, possession of marijuana, contributing to the delinquency of a minor (three of the girls were alleged to be underage), aiding suspected felons, and the alleged rape of a twenty-five-year-old woman, who claimed she was assaulted on the premises the day before. The raid also pertained to a robbery in a nearby alley of a man who was allegedly knocked unconscious and dispossessed of his wallet.Policemen Arrest 48 In Raid On Hell's Angels Marin Independent Journal (December 5, 1964)

A group of Hells Angels members, as well as some of their girlfriends, were charged in connection with a fight which broke out during a birthday celebration at a cafe in San Francisco in September 1965. The violence allegedly erupted when the bikers attacked two police officers who arrived at the establishment.

Sixteen Hells Angels members attacked anti-Vietnam War demonstrators at a Vietnam Day Committee protest march in Berkeley on October 16, 1965, resulting in six Hells Angels being arrested and one police officer suffering a broken leg.Hells Angels vs. Allen Ginsberg: The unlikely Vietnam War-era confrontation Bill Van Niekerken, San Francisco Chronicle (May 15, 2018) The incident led to a collection of students, left-wing political groups and labor unions led by Allen Ginsberg and Jerry Rubin meeting with a group of motorcycle club representatives, headed by the president of the Sacramento HAMC chapter, in the cafeteria at San Jose State College, seeking assurance that a planned protest march in Oakland on November 20 would go undisturbed. On November 19, five Hells Angels members led by the club's reputed national leader Sonny Barger held a press conference at their bail bondsman's office, announcing that the club would not attend the protest the following day as "Any physical encounter would only produce sympathy for this mob of traitors", according to Barger. He went on to read out a telegram sent to President Lyndon B. Johnson, reading "I volunteer a group of loyal Americans for behind the line duty in Vietnam. We feel that a crack group of trained guerillas could demoralize the Viet Cong and advance the cause of freedom."Ralph "Sonny" Barger Confronts VDC / Press Conference sfsu.edu President Johnson did not reply to the letter.Angels, Protesters and Patriots: What a Long-Ago Skirmish Says About Love of Country Chris A. Smith, California (Spring 2016)

Eight Hells Angels were arrested when a fight broke out in a Daly City tavern on April 15, 1966, following the funeral of San Francisco HAMC chapter member Larry Dean Lucas, who died in a motorcycle accident near Santa Maria on April 9.Last Escort for an 'Angel' George Golding, San Mateo Times (April 15, 1966)

For at least five years beginning in 1967, the Oakland chapter of the Hells Angels turned over weapons acquired on the black market or locations of weapons, which could otherwise be used by Black Panther Party and Weather Underground radicals, to the Oakland Police Department (OPD) in exchange for the release of jailed Hells Angels members. OPD sergeant Edward "Ted" Hilliard testified in 1972 that he accepted guns, dynamite and grenades from the club's president Sonny Barger in return for deals on arrests during at least fifteen separate meetings, the most recent of which took place in the spring of 1971.Angels in Court: The Strange Tale of Baby Huey Tim Findley, Rolling Stone (February 15, 1973) Hilliard also testified that Barger had offered "to deliver the bagged body of a leftist for every Angel released from jail". He denied, however, that authorities permitted crimes committed by the Hells Angels.Look Homeward Angel: Cycle Icon Sonny Barger Kick-Starts Life As A Free Man By Violating Parole Philip Martin, Phoenix New Times (December 2, 1992)