Members of nearly every major street gang, including the Bloods, Crips, Black Disciples, Gangster Disciples, Hells Angels, Latin Kings, The 18th Street Gang, Mara Salvatrucha (MS-13), Mexican Mafia, Nortenos, Surenos, Vice Lords, and various white supremacist groups, have been documented on military installations.

Although most prevalent in the Army, the Army Reserves, and the National Guard, gang activity is pervasive throughout all branches of the military and across most ranks but is most common among the junior enlisted ranks, according to the report. The extent of gang presence in the armed services is often difficult to determine since many enlisted gang members conceal their gang affiliation and military authorities may not recognize gang affiliation or may be inclined not to report such incidences.