The 18th Street Gang is a Los Angeles-based Latino/Hispanic street gang. It is considered by many gang analysts to be the largest gang in the United States in terms of membership, and one of the most violent gangs in the world. It is estimated that there are over 20,000 members of 18th Street in Los Angeles County alone.http://www.streetgangs.com/18thstreet.html 18th Street Gang by Alejandro A.