Gangs in the United States
Approximately 1.4 million people in the United States were part of gangs as of 2011, and more than 33,000 gangs were active in the country. These include national street gangs, local street gangs, prison gangs, outlaw motorcycle clubs, and ethnic and organized crime gangs.
Source: Wikipedia — Gangs in the United States (CC BY-SA 4.0)