To Military Assistance Command-Vietnam (MACV), Operation Attleboro was a meeting engagement in War Zone C that grew into the largest operation involving US Forces conducted in South Vietnam at that time. To the Central Office for South Vietnam (COSVN), Operation Attleboro was unexpected early contact by a force attempting to conduct an offensive that snowballed into a desperate defense and fighting withdrawal to protect precious logistic and command capabilities essential to their future operations in III Corps Tactical Zone (III CTZ).
Major General William E. Dupuy (US 1st Infantry Division Commander) and Major General Frederick C. Wyand (Acting Commander, II Field Force, Vietnam) confer during Operation Attleboro in War Zone C on November 14, 1966.
MACV grossly underestimated the National Liberation Front’s (NLF) capability to supply their own forces, tactically maneuver them, and evade detection in order to threaten US/Army of the Republic of Vietnam (ARVN) infrastructure and units when operating in close proximity to Peoples’ Liberation Forces of South Vietnam (PLAF – what are popularly known as “Viet Cong Main Force”) base areas in Cambodia. COSVN grossly underestimated the US’s capability to rapidly reinforce an area of operations using strategic mobility and rapidly employ such reinforcements almost immediately in the field.
Nguyễn Chí Thanh, General Secretary of COSVN and Political Commissar of the Liberation Army of the South, phtographed somewhere in Cambodia in mid-late 1966.
MACV underestimated the proclivity of COSVN to use PLAF forces confront and destroy threats to its logistics and supply system. COSVN erroneously expected US Forces to respond to tactical and operational dilemmas like the ARVN. To wit, responding to “Ambush and Bait” with dispersed pursuits of the ambushers on multiple axis, thus leaving some pursuing units vulnerable to destruction via “One Slow, Four Quick”. Both sides were unaware of flaws and gaps in their respective intelligence, surveillance and reconnaissance (ISR) networks, and the murky picture of active operations that would result from a clash of this magnitude, in the trying terrain of War Zone C. Neither side gained any lasting advantage from Operation Attleboro, though both sides missed opportunities to secure them.
What’s a War Zone C?
War Zone C, located in III CTZ, was a section of South Vietnam with high strategic value. It’s location between Cambodia and Saigon and its daunting, rugged terrain made it an ideal location for a large supply and support zone for PLAF forces and supplies which had been moved down the Ho Chi Minh Trail. War Zone C’s boundaries followed the Cambodian border to the north and west, while its eastern boundary ran parallel to Highway 13. The area included portions of Tay Ninh province, Binh Long province, and Binh Duong province. Intensive efforts had been made since 1960 to develop this zone by the PLAF, and its supplies, reinforcements and replacements were critical to the conduct of COSVN’s operations in what the NLF called Military Region 4 (MR 4 – the Saigon area) and vital to all efforts in the NLF B2 Front (III CTZ and IV CTZ). By 1966, War Zone C was a network of hundreds of cache sites, supply depots, hidden bases and bunker complexes, honeycombed through the low-lying jungle and rugged jungle hills of the area. Several dozen poured concrete bunker complexes were uncovered by the US and ARVN forces in the area as the war progressed. The Saigon river, bisecting War Zone C, was a primary infiltration corridor to the south as cadres and units which had arrived down the trail infiltrated into the heart of South Vietnam. As well, it was an escape corridor to Cambodia for PLAF forces operating in MR 4. War Zone C could be described as a covert logistics and infrastructure hub capable of supporting multi-corps operations.
Ok, so what led to this Operation Attleboro?
A soldier is given a flower by a Vietnamese girl as the 196th Light Infantry Brigade disembarks in Vung Tau, South Vietnam in early August, 1966.
The 196th Light Infantry Brigade (Separate), a green formation utilizing an untested brigade concept, was sent to Tay Ninh Province in the Summer of 1966 (upon its arrival in South Vietnam) to conduct operations in order to disrupt NLF infiltration lines which connected the Ho Chi Minh Trail to base areas in the Saigon area, and degrade and destroy NLF logistics infrastructure that provided forward supply to NLF operations in the III Corps Tactical Zone. MACV had determined that a persistent US presence was required in War Zone C, erroneously assuming that previous operations in the area and in nearby Binh Long province had rendered combat-ineffective PLAF Forces in the area, in particular the 9th PLAF Division, pushing them out of War Zone C. MACV estimated that a US Army brigade in War Zone C would keep them out. MACV also saw this brigade serving as a blocking force that would prevent NLF command and logistics personnel in the Iron Triangle from withdrawing to Cambodia, which had frustrated past efforts (Operation Crimp and Operations Circle Pines, Kalamazoo and others) to clear and remove this threat to the security of the Saigon area. These past operations ultimately failed in the objectives as the PLAF moved to and from the Triangle, War Zone C and Cambodia, variably, successfully avoiding combat with US/ARVN/Australian forces. PLAF forces withdrew largely intact, displaying an inherent weakness in search and destroy operations (the ability of the enemy to merely avoid contact, returning at a later date).
PLAF swearing-in ceremony, date and place is unknown.
The disruption of PLAF logistical networks and operational planning caused by these operations in the first half of 1966, as well as the near containment and destruction of PLAF units in the Iron Triangle by Operation Crimp, induced COSVN to alter its strategic perceptions of the area. COSVN from that point forward was very sensitive to any MACV effort to concentrate offensive power in both War Zone C and the Iron Triangle. COSVN also began to look on with anxiety as increased US interdiction efforts in War Zone C, namely the construction of two additional Special Forces camps (Camps Trai Bi and Minh Thuan) began to interfere with infiltration efforts and logistics operations in War Zone C. The addition of the 196th LIB to the area in the Summer set COSVN on its course of the upcoming dry season; the 9th PLAF Division, reinforced by the newly arrived 101st PAVN Regiment would attack US forces and infrastructure in War Zone C, destroy some of them, and force them out. They had done this the previous year to the ARVN 5th Division, rendering them combat ineffective, repeating the process again as they followed up Operation Birmingham, effectively denying MACV access to the area, despite increases in firepower available due to the drastic expansion of the US combat presence in South Vietnam.
The 196th LIB began Operation Attleboro September 14, 1966 as a series of battalion-size probes around Tây Ninh City, naming the brigade-level operation after the city in Massachusetts, near Fort Devens, where the brigade was formed in 1965. By late October, the operation began to uncover large caches and one supply dump, which indicated that PLAF units were beginning to operate in the province. Simultaneously, US Special Forces Detachment A-322, operating out of Camp Suoi Da, detected a large force of NVA infiltrating into the province, and possibly threatening the camp, causing MACV-SOG to dispatch III CTZ’s Mobile Strike Force Command (MIKE Force) to the area. The 196th Commander was determined to continue efforts to uncover PLAF logistics sites, and engage the suspected PLAF presence near Camp Suoi Da, and was given approval to expand Attleboro by MACV who reinforced him with two infantry battalions from the 2nd Brigade of the US 25th Infantry division (firmly engaged in clearing Cu Chi in the Iron Triangle). And thus began the campaign that became known to history by the mundane sobriquet of “Operation Attleboro.”
PLAF fireteam maneuvers, circa 1966-1967
The result was a month-long clash between what ultimately turned into a division- and a half-sized PLAF/PAVN force and almost two division’s worth of US Army units. A clash that rolled northward to the Cambodian border, as the US vigorously attempted to prevent the withdrawal of, and effect the destruction of, the PLAF combat force and COSVN corps-level logistics and command assets as the NLF tenaciously conducted a fighting withdrawal into Cambodia, desperate to preserve these capabilities. Both sides encountered far more than they bargained for, shed blood, and accomplished little more than the maintenance of the status quo, in the intermediate and long term. In A Hot Dry Season: Operation Attleboro in War Zone C, as the respective commanders of the NLF and US/ARVN forces in Operation Attleboro, the question is, can the players accomplish more?