The Black Guerrilla Family (also known as the Black Family or the Black Vanguard) is a prison

Prison gang

Prison gang is a term used to denote any type of gang activity in prisons and correctional facilities. Prison officials and others in law enforcement use the term security threat group or STG...

 and street gang

Gang

A gang is a group of people who, through the organization, formation, and establishment of an assemblage, share a common identity. In current usage it typically denotes a criminal organization or else a criminal affiliation. In early usage, the word gang referred to a group of workmen...

 founded in 1966 by George Jackson

George Jackson (Black Panther)

George Lester Jackson was an American convict who became a left-wing activist, Marxist, author, a member of the Black Panther Party, and co-founder of the Black Guerrilla Family prison gang...

 and W.L. Nolen while they were incarcerated at San Quentin State Prison

San Quentin State Prison

San Quentin State Prison is a California Department of Corrections and Rehabilitation state prison for men in unincorporated San Quentin, Marin County, California, United States. Opened in July 1852, it is the oldest prison in the state. California's only death row for male inmates, the largest...

 in Marin County, California

Marin County, California

Marin County is a county located in the North San Francisco Bay Area of the U.S. state of California, across the Golden Gate Bridge from San Francisco. As of 2010, the population was 252,409. The county seat is San Rafael and the largest employer is the county government. Marin County is well...

, north of San Francisco.
Inspired by Marcus Garvey

Marcus Garvey

Marcus Mosiah Garvey, Jr., ONH was a Jamaican publisher, journalist, entrepreneur, and orator who was a staunch proponent of the Black Nationalism and Pan-Africanism movements, to which end he founded the Universal Negro Improvement Association and African Communities League...

, the Black Guerrilla Family was characterized as an ideologically based African-American Marxist revolutionary organization composed of prisoners.