The Black Guerrilla Family is a Marxist, African-American gang that was formed in 1966 at San Quentin State Prison in California. The gang was founded by imprisoned Black Panthers, and it was built upon socialist ideals, allying with the Symbionese Liberation Army, Weather Underground, and Black Liberation Army vanguard groups. However, it would eventually morph into a brutal street and prison gang, and it grew to have as many as 300 full members and 50,000 associates.