Conceptions of what constitutes a street gang or a youth gang have varied since the seminal sociological studies on these entities in the 1920s. Organizations of teenage youths and young adults in their twenties, congregating in public spaces and acting collectively, were fixtures of everyday life in American cities throughout the 20th century. While few studies historicize gangs in their own right, historians in a range of subfields cast gangs as key actors in critical dimensions of the American urban experience: the formation and defense of ethno-racial identities and communities; the creation and maintenance of segregated metropolitan spaces; the shaping of gender norms and forms of sociability in working-class districts; the structuring of contentious political mobilization challenging police practices and municipal policies; the evolution of underground and informal economies and organized crime activities; and the epidemic of gun violence that spread through minority communities in many major cities at the end of the 20th and beginning of the 21st centuries.
Although groups of white youths patrolling the streets of working-class neighborhoods and engaging in acts of defensive localism were commonplace in the urban Northeast, Mid-Atlantic, and Midwest states by the mid-19th century, street gangs exploded onto the urban landscape in the early 20th century as a consequence of massive demographic changes related to the wave of immigration from Europe, Asia, and Latin America and the migration of African Americans from the South. As immigrants and migrants moved into urban working-class neighborhoods and industrial workplaces, street gangs proliferated at the boundaries of ethno-racially defined communities, shaping the context within which immigrant and second-generation youths negotiated Americanization and learned the meanings of race and ethnicity. Although social workers in some cities noted the appearance of some female gangs by the 1930s, the milieu of youth gangs during this era was male dominated, and codes of honor and masculinity were often at stake in increasingly violent clashes over territory and resources like parks and beaches.
The interplay of race, ethnicity, and masculinity continued to shape the world of gangs in the 1940s and 1950s, when white male gangs claiming to defend the whiteness of their communities used terror tactics to reinforce the boundaries of ghettos and barrios in many cities. Such aggressions spurred the formation of fighting gangs in black and Latino neighborhoods, where youths entered into at times deadly combat against their aggressors but also fought for honor, respect, and status with rivals within their communities. In the 1960s and 1970s, with civil rights struggles and ideologies of racial empowerment circulating through minority neighborhoods, some of these same gangs, often with the support of community organizers affiliated with political organizations like the Black Panther Party, turned toward defending the rights of their communities and participating in contentious politics. However, such projects were cut short by the fierce repression of gangs in minority communities by local police forces, working at times in collaboration with the Federal Bureau of Investigation. By the mid-1970s, following the withdrawal of the Black Panthers and other mediating organizations from cities like Chicago and Los Angeles, so-called “super-gangs” claiming the allegiance of thousands of youths began federating into opposing camps—“People” against “Folks” in Chicago, “Crips” against “Bloods” in LA—to wage war for control of emerging drug markets. In the 1980s and 1990s, with minority communities dealing with high unemployment, cutbacks in social services, failing schools, hyperincarceration, drug trafficking, gun violence, and toxic relations with increasingly militarized police forces waging local “wars” against drugs and gangs, gangs proliferated in cities throughout the urban Sun Belt. Their prominence within popular and political discourse nationwide made them symbols of the urban crisis and of the cultural deficiencies that some believed had caused it.