Outlaw motorcycle gangs have been a thorn in the side of US law enforcement since the 1960s. Today, these dangerous organizations are engaged in criminal activities on both coasts and throughout the American heartland. “One-percenter” motorcycle clubs—so named because the American Motorcyclist Association has said that 99 percent of motorcyclists are law-abiding—run drugs across the borders and participate in a litany of additional crimes, from contract killing to petty theft. 

Because of their prominent role in the American underworld, outlaw bikers have long been mythologized in film, TV, and literature. Hunter S. Thompson’s book Hell’s Angels brought the gangs’ ruthless behavior to light, and the popular TV show Sons of Anarchy rekindled America’s interest in the subculture. Along with the Hells Angels, gangs like the Mongols, Pagans, and Bandidos are active to this day. In fact, two high-ranking members of the Pagans were recently hit with federal charges for allegedly beating a man they thought was aligned with Hells Angels. Other incidents—like a 2015 gun battle involving hundreds of bikers at a restaurant in Waco, Texas, in which nine people were killed and 18 injured—are reminders that the gangs are both ruthless and here to stay.

Learn who was behind these events with our list of the Most Dangerous Motorcycle Gangs in America.