It is one of the largest criminal gangs in Los Angeles, with 30,000–50,000 members between the United States, Mexico, and Central America and is also allied with the Mexican Mafia, another US-based crime organization.

[19] 18th Street grew by expanding its membership to other nationalities and races, and it was among the first multiracial, multi-ethnic gangs in Los Angeles.

[citation needed] In the early 2000s, the Federal Bureau of Investigation initiated wide-scale raids against known and suspected gang members, netting hundreds of arrests across the country.

[27][15][28][29] In El Salvador, a faction called the "Revolucionarios ("Revolutionaries") split off 18th Street in 2005,[3][30] becoming rivals with the other members, who came to be known as the Sureños ("Southerners.

Los Angeles members began migrating to other areas outside California and started to establish their own gangs.

18th Street gangs are active in 44 cities in 20 U.S. states,[2] as well internationally reported in Australia, Canada, England, France, Germany, Lebanon, Peru, Mexico, Guatemala, Honduras, El Salvador, Venezuela and Philippines.

At the very top are “palabreros” or “leaders,” a majority of these members are in prison, but still help run the gang by coordinating all criminal activities.

Outside of the prisons, Barrio 18 is organized into divisions based on territory called “canchas.” The gang is horizontal in structure, allowing for a more decentralized approach to things.

The 18th Street Gang is occasionally referred to as the "Children's Army" because of its recruitment of elementary and middle-school aged youth.

[41] The most lucrative activity of the 18th Street gang is street-level distribution of cocaine and marijuana, and to a lesser extent, heroin and methamphetamine.

The gang is also involved in auto theft, carjacking, drive-by shootings, extortion, identification fraud, robbery, assault and homicide.

[42] 18th Street Gang has also been implicated in the high-profile kidnapping and murder of the 16-year-old brother of internationally renowned Honduran football player Wilson Palacios.

[44][45] Kingston, New York police arrested and jailed several young men on the charge that they abducted a victim, took him to nearby woods, and murdered him.