Detachment Delta. The CAG—Combat Application Group. ACE—the Army Compartmented Element. Or simply “The Unit.” No matter what you call Delta Force, the U.S. Army’s first and most effective counterterrorism force has been silently protecting America and its allies since the late 1970s, when an upswing in terrorist activity such as bombings and hijackings led the military to create its own elite task force based on the British Special Air Service (SAS).
Colonel Charles Beckwith was chosen to create Delta Force in October 1977. Recruiting heavily among Vietnam veterans, Beckwith culled the finest soldiers from every branch of the military to become part of his new unit. He then endeavored to make them the most fearsome and best-trained soldiers the U.S. had ever produced.
Delta Force conducts its operations via three squadrons: A, B and C. Each squadron is then broken into troops, which consist of four or five groups of four or five men each. Each troop then specializes in air, land or sea attack in an organizational structure based on the British SAS. Troops are also well-prepared enough to be broken down into smaller units, sometimes made up of only one man. In short, a member of Delta Force is equipped to do anything, even alone, to protect America.
Full article: Delta Force: Speed, Surprise and Violence of Action (Newsweek)