Week of December 24
From December 16–19, 1966, elements of the Army’s 9th Infantry Division began arriving in Vietnam. General William C. Westmoreland intended to use the division to increase U.S. presence around the Đồng bằng Sông Cửu Long (Mekong Delta) to improve security and enhance the South Vietnamese Army’s pacification programs already underway.
The Đồng bằng Sông Cửu Long (Mekong Delta) provided a stronghold for the Communist insurgency. Communist operatives used the extensive waterways to move rapidly and establish bases that were largely inaccessible overland. As the most populous and richest agrarian area in South Vietnam, it played a crucial role in the country’s economy. While the South Vietnamese government had resettled much of the rural population into Strategic Hamlets, it held concerns that these underprivileged groups remained particularly susceptible to Communist influence. American advisers estimated that some 45 percent of Việt Cộng strength resided in the Đồng bằng Sông Cửu Long (Mekong Delta).
General Westmoreland created a composite division, designated “Z” Division, to operate in the northern Delta below Sài Gòn. The group included the 9th Infantry Division, and perhaps its most novel feature was its Mobile Riverine Force, which tasked Navy transport and assault vessels with carrying troops from the 9th Infantry Division in amphibious search and destroy operations throughout the area. Troops slogged through terrain dotted with rice paddies, canals, and rivers, facing a climate conducive to infection and natural threats such as poisonous snakes and malaria-transmitting mosquitos.
As the division continued to arrive in early 1967, MACV developed bases in the Delta to stage more effective operations. The 9th Infantry Division needed a base camp with access to waterways, but that did not displace people or cultivated areas. With this in mind, U.S. Army engineers found a vacant rice paddy with enough space, and then dredged sand from the Sông Hậu (Bassac River) to create an elevated area for the base. General Westmoreland designated this new divisional headquarters Đồng Tâm, which translated to “united hands and minds.”1
1Shelby L. Stanton, Vietnam Order of Battle: A Complete Illustrated Reference to U.S. Army Combat and Support Forces in Vietnam, 1961–1973 (Mechanicsburg, PA: Stackpole Books, 2003), 78; Ira A. Hunt, Jr., The 9th Infantry Division in Vietnam: Unparalleled and Unequalled (Lexington, KY: The University Press of Kentucky, 2010), 4–9; George L. MacGarrigle, Taking the Offensive, October 1966 to October 1967, United States Army in Vietnam (Washington, D.C.: Center of Military History, United States Army, 1998), 15, 394–397; Robert R. Ploger, U.S. Army Engineers, 1965–1970, Vietnam Studies (Washington, D.C.: Department of the Army, 2000), 136, 145–147.