Operation Union was a military operation conducted by the United States Marine Corps during the Vietnam War. It was a search and destroy mission in the Que Son Valley carried out by the 1st Marine Regiment. The object of the operation was the 2nd Division of the People’s Army of Vietnam (PAVN, often in US sources "North Vietnamese Army" or NVA). Launched on April 21, 1967 the operation ended May 16.
The Que Son Valley is located along the border of Quang Nam and Quang Tin provinces. During the Vietnam War it lay in the southern part of South Vietnam's I Corps Military Region.
Populous and rice-rich, the valley was viewed as one of the keys to controlling South Vietnam's five northern provinces by the communists and by early 1967 at least two regiments of the 2nd Division of the PAVN had been infiltrated into the area. The Que Son Valley was also recognized as strategically important by Military Assistance Command, Vietnam (MACV). The 5th Marine Regiment minus its 2nd Battalion, an experienced force that had fought in Vietnam since their arrival in the Summer of 1966, was assigned to the valley in 1967 to support the outnumbered the Army of the Republic of Vietnam (ARVN) forces in the area, the 6th ARVN Regiment and the 1st ARVN Ranger Group.
Since mid-January 1967 Foxtrot Company, a reinforced company of the 2nd Battalion 1st Marines (F/2/1), had manned an outpost atop Nui Loc Son (Loc Son Mountain), which dominated the southern Que Son Valley. Although the Communist forces operating in the valley did not initially take much notice of the Marines, on April 15, 1967 the Foxtrot company commander advised Colonel Emil Radics, the commander of the 1st Marine Regiment, that enemy units appeared to be preparing for an all-out assault on the outpost.
Radics developed a plan for a multi-battalion assault and sweep aimed at clearing PAVN units from the vicinity of the mountain. The plan was approved as Operation Union by Major General Herman Nickerson, the com...