Territory: Midwest and South
Approximate membership: 250-275
This Colorado-based gang is one of the smallest on our list, but what they lack in numbers, they make up for in ruthlessness. The Sons of Silence have been embroiled in turf wars for decades. They initially carved out territory in Colorado, Arizona, and Kansas, and later aligned with the Hells Angels for protection. That made them a target for smaller clubs, which explains why a 1999 clubhouse raid turned up machine guns, pipe bombs, and grenades.