Operation Cedar Falls: Search and Destroy in the Iron Triangle | HistoryNet

“The purpose here is to deprive the Viet Cong of this area for good”

At dusk on October 8, 1965, barely 90 days after the U.S. Army’s 1st Infantry Division began arriving in Vietnam, three of its infantry companies trudged out of a heavily forested area. The soldiers mounted trucks to return to their base, eagerly anticipating showers, hot food and rest after three weeks of chasing the elusive Viet Cong. However, in the gathering darkness, shots suddenly rang out and a desperate and chaotic firefight erupted as the startled Americans poured fire at muzzle blasts coming from the dense foliage. Then, as the Viet Cong (VC) shooting gradually diminished, their mortar rounds began falling among the trucks. When it was all over, six men of the 1st Battalion, 18th Infantry lay dead and 40 more were wounded. At dawn the next day, no VC bodies were found, but there was evidence some had been carried away.

The vicious fight was just 30 miles north of Saigon in a 115-square-mile patch of jungle ominously known as the Iron Triangle.

The Iron Triangle was so heavily defended, forested and fortified that it would be another 15 months before there were enough U.S. troops in-country to field a force adequate to successfully assault this VC bastion. Operation Cedar Falls, the largest U.S. operation in the war to date, would have a number of significant results. It would validate the effectiveness of a new intelligence methodology; ignite disputes among U.S. military leaders; expose serious weaknesses in South Vietnam’s ability to care for refugees and the need for a better organization for U.S. pacification assistance agencies; and produce fodder for the nascent antiwar movement at home. Most critically, Cedar Falls would demonstrate that General William Westmoreland was not wholly devoted to the “big-unit” war, as his detractors claimed. Also—and often overlooked—Cedar Falls directly contributed to the tepid South Vietnamese response to North Vietnam’s call for a “General Uprising” during the Tet Offensive.







At the same time American military leaders grappled with how to deal with the Iron Triangle, a serious argument over North Vietnamese strategy roiled Hanoi. General Vo Nguyen Giap, commander of the People’s Army of Vietnam (PAVN), had been convinced in late 1965 that his troops could not sustain the large losses they were suffering in the South against superior U.S. firepower and mobility. Through 1966, Giap pressed for a reversion to guerrilla warfare methods instead of continuing the main force struggle between his regulars and allied forces. Giap lost the argument to Hanoi’s commander in the South, General Nguyen Chi Than, who not only favored the big-unit war, but also believed Southerners would join in a revolt against the Americans and their puppets in Saigon. In April 1967, Hanoi secretly directed preparations for an all-out offensive and general uprising in the South.

During the last days of 1966, when the Giap-Than controversy was still going on in Hanoi, General Westmoreland settled a similar argument among his generals. I witnessed this when I accompanied my commander, Maj. Gen. Fred Weyand, leading the 25th Infantry Division, to Lt. Gen. Jonathan Seaman’s II Field Force headquarters at Long Binh, 22 miles northeast of Saigon. We were first briefed on pattern activity analysis, the intelligence technique that was being used to pinpoint the several segments of a Viet Cong headquarters and logistical complex in the Iron Triangle, Military Region IV (MR4).

Then Seaman, a tall, dour 55-year-old veteran of both the European and Pacific theaters in World War II and recent commander of the 1st Infantry Division, recommended that Westmoreland revise the timing of a long-planned operation against enemy main forces in War Zone C, 60 miles northwest, in order to throw a two-division force against the Iron Triangle. The mission would be to destroy this base and the local and guerrilla forces there—units that had recently conducted guerrilla actions in and around Saigon.


A member of "A" Co., 1/26th, 1st Bde, 1st Inf Div crouches near a tree while waiting for the area ahead to be cleared of mines, during Operation Cedar Falls in the Iron Triangle. (National Archives)
A member of "A" Co., 1/26th, 1st Bde, 1st Inf Div crouches near a tree while waiting for the area ahead to be cleared of mines, during Operation Cedar Falls in the Iron Triangle. (National Archives)
Major General William DePuy, leading the 1st Infantry Division, objected to Seaman’s proposal and strongly advocated striking a VC main force unit instead. A rising star in the U.S. Army, the 48-year-old DePuy, described by one observer as a “small, tough, battle-wise, brainy and innovative leader,” had a formidable reputation and had recently served as Westmoreland’s operations officer. Seaman expected Westmoreland would side with DePuy, but surprisingly, Westmoreland told Seaman, “You are the commander, the decision is yours.”

Operation Cedar Falls, named for the hometown of 1st Division Medal of Honor recipient Robert John Hibbs, who had been killed in March 1966, would involve a massive sweep of the Triangle by two brigades of DePuy’s division, plus an airborne brigade, elements of a cavalry regiment and an Army of the Republic of Vietnam (ARVN) Ranger battalion.

Meanwhile, Weyand, employing two brigades, would sweep through wooded areas west of the Saigon River and block any enemy escape attempt to avoid DePuy’s assault. Units on the sweeps were given a “VC Installations List” detailing the location, unit or office designations of all facilities, depots, communications centers and expected positions of three local force VC battalions and two separate companies. No enemy main force units were expected to be in the Iron Triangle. All of the estimated 6,000 inhabitants of the Triangle’s one village and several outlying hamlets would be assembled, screened and relocated. The plan called for the destruction of all enemy installations within a two-week period, after which the Triangle would be publicly designated a free-fire zone—where any inhabitant would be considered hostile.

Ben Suc, the Triangle’s main village of about 3,500 people, already had a martial history and unfortunate experience with political coercion. A sprawling collection of houses, rice paddies, orchards and shops, Ben Suc had been fortified as far back as the late 18th century, when it was the base for operations against rebellious northern tribes. The village had been the site of an ARVN outpost until the Viet Cong overran it in 1964, executed the village chief, blocked the roads and organized the population into youth, women and farmers associations and indoctrinated them on National Liberation Front (NLF) goals and laws.

The villagers were told the Americans were evil, that they killed pregnant women and ate their victims. They were required to pay taxes in rice and other foodstuffs or money, supply recruits for VC units, transport supplies and clear battlefields of the dead. The civilians also supplied the labor to dig fighting trenches and bunkers for combat units and tunnels to shelter political, medical, communication and other such stationary facilities. The ARVN had attempted to recover Ben Suc before, but it and the Iron Triangle had been in VC hands for about two years.

At the direction of General Seaman, who believed VC agents had penetrated several ARVN headquarters, Cedar Falls was held in strict secrecy—even from some of the participating ARVN allies—until the day before its January 8 launch. On January 7, six newsmen were given a briefing on Cedar Falls, including 24-year-old Jonathan Schell of the New Yorker, who recorded the briefing by Major Allen C. Dixon. Pointing to a map, the major began: “We have two targets, actually. There’s the Iron Triangle, and then there’s the village of Ben Suc.” Dixon called the village a “solid VC” political center. “We know there’s important VC infrastructure there,” he said. “What we’re really after is the infrastructure. We’ve run several operations in this area before with ARVN but it’s always been hit and run. You go in there, leave the same day and the VC are back that night. This time we’re really going to do a thorough job of it; we’re going to clean out the place completely. The people are all going to be resettled in a temporary camp near Phu Cuong, the provincial capital down the river, and then we’re going to move everything out—livestock, furniture and all of their possessions. The purpose here is to deprive the VC of this area for good.”

Dixon told the reporters that 500 1st Division troops would land in 60 helicopters around Ben Suc at 0800, to avoid mines and booby traps that were on the village’s approaches. A helicopter with loudspeakers would instruct villagers to assemble at the village center and inform them that anyone attempting escape would be considered Viet Cong. Safe conduct pass leaflets would be dropped for any VC desiring to defect. Dixon said the villagers would be evacuated and cared for by incoming ARVN units—which would be briefed on their role shortly before they were brought to the Triangle.

The next morning, January 8, reporter Schell joined troops of the 1st Division’s 1st Battalion, 26th Infantry Regiment, under the command of Lt. Col. Alexander Haig at Dau Tieng, 11 miles north of Ben Suc. They flew due south at 2,500 feet, within sight of the village but on a path that appeared well to the west of Ben Suc. Gradually losing altitude, the 60 helicopters disappeared from the village’s view, and then turned toward it at treetop level, roaring forward at 100 mph. Flaring out at precisely 0800, the helicopters drifted down on three landing zones around Ben Suc. Surprise was complete and the village was quickly surrounded. Sporadic firing faded away.

After the helicopters left to pick up more troops, a lone Huey circled above, giving instructions to the inhabitants through a loudspeaker. Well to the north, U.S. artillery fire began hitting designated landing zones in preparation for helicopter-borne assaults into the nearby wood. Within an hour, as they had been ordered to do, about 1,000 villagers had gathered at Ben Suc’s school. South Vietnamese police and ARVN troops then arrived to screen the villagers and cull males between 15 and 45. A 1st Division field kitchen was set up and a medical tent was erected so U.S. medics could offer treatment to the waiting inhabitants. A detailed search of the villagers’ homes by ARVN soldiers began. By midafternoon, some 3,500 dejected and unfriendly villagers had been assembled. It was looking like Cedar Falls might be a textbook piece of allied military precision.

That’s when things soured. While New Yorker reporter Schell was observing the operation around Ben Suc, he came on an ugly scene of ARVN officers interrogating some young males. The suspects, who failed to answer questions to the officers’ satisfaction, were repeatedly beaten—all this, Schell wrote, under the eyes of “a very fat American with a red face and an expression of perfect boredom.” When a U.S. Army captain arrived on the scene, he took Schell aside and said, “You see, they do have some, well, methods and practices that we are not accustomed to, that we wouldn’t use…but the thing you’ve got to understand is that this is an Asian country, and their first impulse is force.”

Soon, the evacuation plan for the families quickly unraveled. While Seaman’s secretive planning yielded a thoroughly surprised enemy, it also produced distrust between the allies, an agonizing delay in the operation, and perhaps worse. All of the military-age males were flown to Phu Cuong for interrogation in the afternoon, but the unexpected and hasty effort to round up enough ARVN landing craft to transport the families, their animals and possessions on the Saigon River from Ben Suc to Phu Cuong broke down. South Vietnamese authorities, angry with their pushy, inconsiderate American allies, simply had not had the time to identify, plan, assemble and supervise a flotilla, resulting in a two-day delay. On January 10, General DePuy, disgusted and impatient with the handling of the refugees, took charge. He organized truck convoys to transport some families to the provincial capital and ordered the landing craft be used to bring the rest of the villagers and the farmers’ water buffalos.

Meanwhile, searching and fighting was progressing in the woods surrounding Ben Suc. Since landing, 1st Division troops had discovered several tunnel complexes and stores of foodstuffs, ammunition and other supplies. Some of the surprised Viet Cong fought back, and early fighting left 40 dead, while the Americans were initially free of battle deaths. The biggest fight of the entire operation took place across the river in the 25th Division area when a 2nd Brigade unit made an unexpected, sharp contact with a battalion-size enemy force during an air assault. This bloody action continued for most of the day with men of the 1st Battalion, 27th Infantry breaking up the enemy battalion and chasing down groups of its survivors. In this hot, deadly fight, six Americans died, while the VC left 100 bodies of their outgunned battalion on the field.

As the sweep of the Triangle continued for two weeks, many smaller actions took place, but the main role of U.S. forces became locating, searching and destroying hundreds of tunnels. The GIs soon learned how to spot a tunnel entrance, entice any enemy out of it, and then send a pistol-armed volunteer, or “tunnel rat,” inside with flashlight, compass and field phone, to explore and retrieve documents, weapons and ammunition. The tunnel would then be destroyed by explosives or by pumping acetylene gas into the passageways and igniting it.

A notable exception to the largely passive response to the U.S. sweep of the Triangle came when the 1st Battalion, 28th Infantry, entered the woods just northeast of Ben Suc, looking for a previously identified VC installation. The facility was a camouflaged medical supply depot with a tunnel being used as a hospital, where Dr. Vo Hoang Le, his wife and several assistants were tending to 60 patients. Alerted by the Ben Suc attack, Dr. Le decided to ignore instructions to flee or hide from the Americans and opted to arm his staff, prepare concealed firing positions and defend his hospital with four rifles, a Thompson submachine gun and his own .45-cal. revolver.

The next day, at 1230, Dr. Le saw three American soldiers approaching. When they were within 20 feet, he began firing, killing all three. Le’s wife scurried through a blizzard of American bullets to the American bodies and returned with their M-16s and some ammunition. Spotting a GI crawling forward to retrieve one of the bodies, Le killed him. The Americans called in artillery and an airstrike with napalm. In the afternoon, the Americans launched three attacks, each pushed back by Le and the defenders. The doctor later recalled: “That night, I raised the question of withdrawing. Some of my comrades were against the idea….I told them if we stayed, we would not be able to withstand the next day’s assault….We left six of the wounded behind in secret tunnels; they had lost legs or had head wounds and could not walk. Two nurses stayed to look after them….We went through the shell fire….Two men were wounded during the journey, but none were killed.”

On January 11, an argument about the treatment of the refugees arose among U.S. and South Vietnamese leaders. It involved General DePuy and the head of the regional U.S. Agency for International Development (USAID) office, John Paul Vann. An ex-U.S. Army lieutenant colonel, Vann was a courageous, intelligent 43-year-old former Ranger who had been an adviser in Vietnam in 1962-63, and had keen insights into Vietnamese culture. The dispute began with DePuy’s quick inspection of the Phu Cuong reception camp and his outrage at the lack of adequate organization, sanitation, shelter, food and medical services for the refugees. DePuy complained about the abysmal conditions to General Seaman and suggested that he take charge of the camp, as he’d taken charge of the evacuation. Seaman reaffirmed his desire to have the Vietnamese take care of their own people with Vann’s assistance in supplying resources. Vann phoned DePuy to see if he could relieve the general’s concerns and got an angry response: “Vann, your lousy organization has fallen flat on its face and I am going to move in and do the job—as usual!” Vann countered that the Vietnamese authorities were responsible for the camp’s shortcomings and the reason behind that stemmed from their belief that the refugees had no loyalty to the Saigon government.

Within a few days, the refugees’ plight was somewhat eased with the arrival of tents, clothing, food and water and sanitary facilities—much of it coming from the 1st Division. Five months later, under Vann’s hand, the refugees were living in concrete block buildings with metal roofs, fairly well supplied and maintaining the same standard of living as the dependents of ARVN soldiers. However, no one involved in the evacuation dispute was truly satisfied—least of all, the refugees themselves.

Up in the Triangle and the 25th Division’s search area, the destruction of Military Region IV facilities continued until January 26, when Operation Cedar Falls ended. Vietnamese paratroopers assumed the search of Ben Suc and made the most stunning find yet. The VC had taken advantage of the allied proclivity to avoid hitting villages with artillery and airstrikes, and had dug a vast, three-story-deep complex of tunnels and chambers covering several acres underneath the village. There were offices, medical facilities, storage bins and spaces for the manufacture of clothing, munitions and footwear, even special defense capabilities—tunnels leading to surface observation and firing positions.

Elsewhere, other facilities were found, including several underground VC provincial and district government headquarters. MR4’s signal and cryptographic center was located, along with files and code books. Its intelligence section contained a trove of documents, including more than 200 personal history sheets on cadre and a notebook of names of ARVN officers who were supplying the VC with information and U.S. ammunition. The postal, communications and transportation section was found with extensive records, and an operations office was also identified, yielding campaign plans and maps. A number of camouflaged, aboveground rice storage facilities were also found, shielding hundreds of tons of bagged rice.

The results of Operation Cedar Falls were impressive, as more than four square miles of jungle had been cleared. The allies had captured 578 weapons and 3,700 tons of rice—enough to feed five regiments for a year. Eleven hundred bunkers, 424 tunnels and 509 structures were destroyed. The effectiveness of pattern activity analysis had been confirmed. Viet Cong losses included 723 killed and 213 taken prisoner, among them 12 high-ranking officials and MR4’s talkative operations officer, who was caught trying to spirit away two pounds of documents and maps. More than 500 enemy personnel defected and some 500,000 pages of documents were seized. Within a few days, police and ARVN counterintelligence authorities began picking up enemy agents and traitors, and breaking up underground networks throughout the region and in Saigon. Almost immediately, incidences of assassination, sabotage and guerrilla actions in the region dramatically dropped. The cost included 72 American and ARVN battle deaths.

However otherwise impressive, the results also lent fuel to a growing chorus of American rejection of U.S. war policy and a belief among some critics that the operation had failed, since it had not completely and permanently removed the enemy from the Triangle. But the spark for widespread public unease did not come until reporter Schell’s New Yorker article appeared in July, telling the sad fate of Ben Suc’s hapless refugees. Within a year, Schell’s entire report had been published as a book, The Village of Ben Suc, that was widely referenced by opponents of the war.

Some Viet Cong did return to the Iron Triangle after the operation, but keeping them out would have required a defending force of considerable size, which the allies believed to be an unwise use of scarce soldiers. The Viet Cong who did return found life in a free-fire zone perilous and challenging without villagers to supply labor, recruits and food.

Cedar Falls yielded two positive results that leaders could not have envisioned when they planned the operation. The evacuation and settlement of the Triangle’s refugees was so flawed that the Civilian Operations and Revolutionary Development Support (CORDS) organization was created three months later. An ambassadorial-level civilian, reporting to the commander of the Military Assistance Command, Vietnam, led the organization. This integrated military-civilian structure proved superior and gave Westmoreland the authority to direct U.S. pacification support along with military advisory and combat operations.

The other unanticipated achievement was the massive collection of documents that led to the arrests of key Viet Cong agents and officials in Saigon and its environs. Although unknown to the American planners of Cedar Falls, the subsequent weakening of the National Liberation Front infrastructure in the Saigon region would diminish the chances for success of the General Uprising then being secretly planned by COSVN.

Later, in confidential documents that circulated among Communist leaders, the Viet Cong admitted that Operation Cedar Falls had, for them, been a great disaster.