JUNCTION CITY was to be the largest operation of the Vietnam war to date and the second one under control of II Field Force, Vietnam. Its primary mission would be search and destroy to eradicate the Central Office of South Vietnam (COSVN) and Viet Cong and North Vietnamese Army installations. Also, various installations such as Special Forces camps and airfields were to be built. Two U.S. divisions, with the commitment of as many as twenty-two U.S. infantry battalions, fourteen artillery battalions, and four South Vietnamese battalions would be involved. JUNCTION CITY would also include the first major combat parachute assault since the Korean War.
Like the Iron Triangle, War Zone C was a major Viet Cong stronghold and had been a sanctuary for insurgents for over twenty years. It was also believed to be the location of headquarters of the Central Office of South Vietnam; however, owing to the remote-ness of the area and the strict secrecy with which the enemy treated the headquarters, few facts were known about COSVN installations and units in the area. Clandestine operations conducted in Sep-tember of 1966 and during Operation ATTLEBORO in November had, however, developed significant intelligence on War Zone C.
In discussing the genesis of Operation JUNCTION CITY, General Seaman, commanding general of II Field Force, Vietnam, stated:
I've got to go back to Operation "Birmingham" which was con-ducted by the 1st Division in War Zone C, in May of 1966. It was conducted along the Cambodian Border as far north as Lo Go (about 30 kilometers northwest of Tay Ninh City) and the plan was to airlift a brigade into the then suspected location of COSVN headquarters. The 1st Division airlifted one battalion to the area, intending to get an entire brigade there within the day; but, unfortunately, the weather closed in and the rainy sea-son started a couple of weeks earlier than anticipated. So, the decision was made by the division commander, MG DePuy, to withdraw that one bat-talion, feeling that he could not reinforce it if they got into any difficulty.
Following Operation "Birmingham," General Westmoreland said he wanted me to plan an operation in War Zone C to start as soon as possible after the Christmas and New Year's stand-downs of 1966-1967. He said, in effect, "to think big." This operation was to start about the 8th of January
1967, and would be a multi-division operation including an airborne drop. I (later) briefed General Westmoreland on the progress of our plans for "Junction City" and he approved my concept.
The operation plan, originally named GADSDEN, had three mayor objectives: to engage the 9th Viet Cong Division and the 101st North Vietnamese Army Regiment; to destroy COSVN head-quarters; and to destroy enemy base camps and installations in the area of operation. The plans included a parachute assault by both the 1st Brigade, 101st Airborne Division, and the 173d Airborne Brigade. Among other objectives, the operation was intended to convince the enemy that War Zone C was no longer a haven.
The concept included deception operations prior to the main thrust into War Zone C. During this initial phase, units and sup-plies would be positioned to support the follow-up effort.
Definitive planning for the operation started in late November 1966. With all intelligence sources of II Field Force, Vietnam, oriented toward collection of information on the operational area, more and more data were received as the starting date for the operation neared. Pattern activity analysis was used extensively, as it had been for Cedar Falls; much of the data acquired in that operation was applied in planning Junction City. Information on the general location of COSVN and the movements of enemy units of interest was further refined.
From the first planning conference, strict security measures were enforced to prevent compromise. The planning group was held to a minimum within II Field Force, Vietnam, headquarters; whenever possible, preparations were made without specifically identifying them with the operation. However, in December the name of the main operation was changed to JUNCTION CITY because it was believed that the name GADSDEN had been com-promised. GADSDEN was shifted to one of the two planned deception operations.
Operation GADSDEN was to be conducted by the U.S. 25th Divi-sion in the extreme western portion of War Zone C, in the vicinity of Lo Go. The second preliminary operation, named TUCSON, would be conducted by the U.S. 1st Infantry Division in Binh Long Province, eighty kilometers to the east, in an area generally de-fined by the Minh Thanh and Michelin rubber plantations and the village of Bau Long on Highway 13. This area also comprised the northern portion of the Long Nguyen secret zone.
Both these preliminary actions were designed as individual division operations in the proximity of the normal division tac-tical areas of interest. In addition to moving forces for GADSEN and TUCSON, providing a cover for friendly troop buildup on the edges
of War Zone C, and establishing supply bases for JUNCTION CITY, it was envisioned that the deception could possibly cause the 271st and 272d Viet Cong Regiments to move into the central area of War Zone C from their then suspected locations.
The plans for JUNCTION CITY, GADSDEN, and TUCSON were pub-lished in early December 1966. D-days were set as 3 January for GADSDEN and TUCSON and as 12 January for JUNCTION CITY.
However, as was discussed above, in the middle of December General McChristian, Military Assistance Command J-2, briefed General Seaman on information concerning enemy activities in the Iron Triangle which led to the decision that Operation CEDAR FALLS would be conducted in January. JUNCTION CITY would be postponed until later in February; in turn, GADSDEN was delayed until 2 February and TUCSON postponed until 14 February.
The intelligence concerning War Zone C was continuously being re-examined, and in mid-January the movement and reloca-tion of the 9tb Viet Cong Division and the enemy regiments were established. The 271st Regiment was located on the Cambodian border near Lo Go, the 272d Regiment had moved to the Michelin rubber plantation northeast of Dau Tieng, and the 273d was now located outside War Zone C near Tan Uyen, about twenty-five kilometers northeast of Saigon.
The 271st and 272d were added as targets for Operations GADSDEN and TUCSON. Headquarters of the 9th Viet Cong Division remained in the eastern sector of War Zone C while intelligence indicated the 101st North Vietnamese Army Regiment- now listed as subordinate to the 9th Division- had moved north to the vicinity of An Loc and Loc Ninh. This new and significant information on the location of enemy units resulted in a shift in the area of primary interest from the eastern to the west central section of War Zone C. The target of major interest became the COSVN headquarters elements.
As D-day for JUNCTION CITY approached, II Field Force intelli-gence analysts provided these conclusions about the enemy:
In view of the enemy's recent setbacks in Operation Cedar Falls, and in Tay Ninh Province (ATTLEBORO), the political rejection of the VC by the populace in the national elections (September 1966), and his fail-ure to achieve a major significant victory, the VC will increase guerrilla warfare and terrorism in an effort to wear down and tire the Free World Forces employed in Vietnam. The enemy will use his main forces, when ready, to attack targets that represent significant psychological victories at a minimum risk to his own forces.
The intelligence report listed the following probable enemy courses of action:
1. Intensify guerrilla warfare, acts of terrorism, harassment, propa-ganda and interdiction of lines of communication.
2. Conduct less than regimental size attacks against isolated forces and installations.
3. Withdraw from main US combat units if he considers the situation unsuitable for a decisive victory.
4. Attack selected targets with forces of regimental strength at a time and place of his own choosing.
5. Continue to secure his base areas and lines of communication.
Events over the next two months would validate these predic-tions.
The operational area for Junction City, War Zone C, is gener-ally defined as the 80x50-kilometer area bounded on the west and north by Cambodia, on the east by Highway 13, and on the south by an east-west line drawn through Ben Cat and Tay Ninh and extending to the Cambodian border. The terrain in the northern and eastern portions rises to approximately one hundred fifty meters while the southern and western portions range in elevation from five to fifty meters. The generally flat, marshy land in the west changes to gently rolling terrain, finally becoming irregular near the eastern province boundary.
The predominant land fea-ture in the area is the 987-meter-high Nui Ba Den. Two major rivers drain the area: the Vam Co Dong on the west and the Saigon on the east; neither is fordable. Numerous small streams are found in the eastern portion of War Zone C, the principal ones having steep banks and muddy bottoms.
In the south, trafficability in the area of interest varied from good in the rubber plantations to difficult in marshy areas. In the north, particularly the northeast, movement was difficult because of the heavy forests and dense undergrowth and bamboo but im-proved in the north and western portions of the province because of the relatively thin forests and scattered open areas.
The ground was expected to be relatively dry during most of the operation. For all practical purposes, at the time JUNCTION CITY was initiated all significant bridges in the operational area had been destroyed, although footbridges had been constructed by the enemy on many of the trails that crisscrossed the area.
At the beginning of JUNCTION CITY the skies over the operational area would be clear, with little precipitation. Later, some rain and cloudiness would occur with patchy early morning fog, limiting visibility in some instances to one mile. The fog generally would dissipate by midmorning. Temperatures would range from a high of 95 to a low of 59 degrees.
Because of the vast area to be covered, the difficult terrain, the enemy anticipated, the number and types of units involved, and the diversity in operations, the planning for JUNCTION CITY was extensive and complex. The mission assigned the planners of II Field Force, Vietnam, read:
a. Phase I-On order, II FFORCEV in coordination and cooperation with the m ARVN corps conducts a major offensive into War Zone C (northern Tay Ninh Province) to destroy COSVN and VC/NVA forces and installations.
b. Phase II-On order, II FFORCEV conducts coordinated airmobile and ground cults in eastern War Zone C to destroy COSVN and VC/NVA forces and installations.
As originally planned, JUNCTION CITY was to have had only two phases; however, because of the success achieved, Phase III would later be initiated. Its mission: "Continued search and destroy operations north of Highway 247, secure Highway 26 south from Tay Ninh to the junction of Route 239 and secure the towns of Tay Ninh and Suoi Da." Initially two South Vietnamese regiments were to have participated; however, by January 1967 it was evident that this number was too ambitious and it was reduced to four battalions. In addition, the 1st Brigade of the U.S. 101st Airborne Division was not made available.
As envisioned by II Field Force, preliminary operations GADSDEN and TUCSON, jumping off on 2 and 14 February respectively, would position forces and materiel on the western and eastern extremities of the area of operations. Phase I of JUNCTION CITY would commence on 22 February with five U.S. brigades forming a horseshoe shaped cordon in the western half of War Zone C. (Map 8) The 25th Division would block on the west along the Cambodian border; on the north, along the border, and on the east along Provincial Route 4 would be the 1st Infantry Division with the 173d Brigade attached. On D plus 1 a brigade of the 25th Division and the 11th Armored Cavalry Regiment (attached to the 25th), which had positioned themselves on the southern edge of the horseshoe the previous day, would attack north into the horseshoe.
The horseshoe forces would conduct search and destroy operations in their areas. Simultaneous with the detailed and thorough search, a Special Forces and Civilian Irregular Defense Group camp near Prek Klok would be established for future interdiction of enemy supply and infiltration routes in War Zone C. An airstrip capable of handling C-130's would be constructed at the camp. A second similar airfield would be constructed in the vicinity of Katum.
During the operation, particular attention was to be devoted to searching suspected locations of the political and military elements of the Central Office of South Vietnam. A thorough interrogation of all persons apprehended was to be conducted.
During Phase II, II Field Force elements would focus their attention on the eastern portion of War Zone C, conducting search and destroy operations against COSVN, Viet Cong, and North Vietnamese forces and installations. The Saigon River was to be bridged at its intersection with Route 246 west of An Loc. At that site a Special Forces and Civilian Irregular Defense Group camp with an airstrip for C-130's was to be built.
In Phase III, Junction City would be reduced to a brigade-size operation in the vicinity of Tay Ninh city in the southern portion of War Zone C. The operational control for this phase would be passed from II Field Force to the 25th Infantry Division.
Operation JUNCTION City would demonstrate the ability of American forces to enter areas which had been Viet Cong sanctuaries to conduct successful search and destroy missions and construct facilities in these strongholds. In addition, in the weeks forthcoming each of the four enemy regiments under the 9th Viet Cong Division would be met and defeated.
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