Operation Cedar Falls: Vietnam War's Largest Ground Operation

Introduction

Operation Cedar Falls took place during the Vietnam War in January 1967. It was an operation designed to create a no man's land by forcing civilians to leave their rural villages and migrate to the cities. The United States military launched it to remove Vietcong forces from the Iron Triangle region north of Saigon, while also clearing out civilians believed to be sympathetic to the Communist cause. It was a highly controversial operation that raised serious questions about how the military conducted evacuations and treated civilians during the assault.

The Vietnam War

The Vietnam War took place between 1959 and 1975. U.S. participation began initially with military advisors sent to support the South Vietnamese Army, which was engaged in battle against the Communist North Vietnamese Army. A South Vietnamese communist force known as the Vietcong also fought against the South Vietnamese government. U.S. troops arrived in the region in 1961, and combat troops were officially deployed in 1965.

The war continued until 1975, when the United States withdrew and the country fell to North Vietnam, becoming Communist. Nearly 60,000 U.S. troops died in the conflict, with millions of civilian casualties. Extremely unpopular with many Americans, protesters and activists worked for years to end U.S. involvement. The United States officially stopped deploying additional troops in 1973, following a Congressional act that prohibited sending further forces. It was a victory for the antiwar movement. Eventually, North Vietnamese forces overran Saigon and the war ended.

Leading Up to Cedar Falls

In the province of Binh Duong, north of Saigon near the Cambodian border, North Vietnamese and Vietcong forces controlled the territory and U.S. forces could not break through their defenses. One author notes, "The operations of American ground forces achieved a stalemate. In Binh Chanh, as in many other districts, they held the Viet Cong at bay but did not defeat it. If the Americans were to leave Gia Dinh, a South Vietnamese intelligence officer predicted in May 1967, 'the VC will attack Saigon within a week.'"

Military planners determined that the area needed to be cleared of North Vietnamese and Vietcong troops, and they designed an operation to accomplish exactly that. It would be launched in January 1967. The targeted area was known as the "Iron Triangle," a Communist stronghold for more than two decades — dating as far back as Ho Chi Minh's Communist army, the Vietminh, which had operated there against the French.

Another writer notes, "For over twenty years, the Iron Triangle had been a headquarters, staging area, and supply point for communist forces. Although sparsely populated, the Iron Triangle as well as the two war zones was strategically important." Military leaders also believed that many civilians in the area supported the Communists, and therefore wanted to clear them from the region as well.

Operation Cedar Falls and Military Operations

In order to gain control of the province and clear civilians from the area, the military worked with South Vietnamese troops to launch Operation Cedar Falls. The operation involved 30,000 American and South Vietnamese troops. It was historically significant as the first major corps-sized American mission of the war, as well as the first major combined U.S.–ARVN operation involving formal planning. It was also a chance to demonstrate how the two forces could work effectively together, and it was critical to the protection of Saigon, located only 30 miles to the south. In addition, it became the largest ground operation of the entire Vietnam War.

Several divisions and regiments participated. Author Stanton notes, "The 1st Infantry Division, 173d Airborne Brigade, and the 11th Armored Cavalry Regiment would then crash right through the Iron Triangle from its eastern side, splitting it in two, and hammer the enemy against the anvil." Altogether, 22 battalions took part in the operation.

The assault began in the village of Ben Suc — the same village that had experienced so many difficulties during the civilian evacuation. The opening barrage involved sixty helicopters packed with troops and ten helicopter gunships. Author Stanton describes the execution: "The helicopters, loaded with soldiers of Lt. Col. Alexander M. Haig's 1st Battalion, 26th Infantry, roared over the forests at treetop level. Skipping the usual preparatory bombardment to achieve surprise, they landed in the midst of the village and cordoned it off." The attack was so swift and unexpected that Vietcong and North Vietnamese forces were stunned and offered little resistance, though there were some casualties from mines and sniper fire.

U.S. soldiers discovered a series of tunnels and storage rooms concealed beneath houses in the village. After removing the villagers, forces bulldozed the entire village, eliminating the Vietcong stronghold. Ben Suc, however, was only the first phase of the broader Cedar Falls operation. Author Stanton notes, "The rest of the 1st and 25th Infantry Divisions sealed off the other legs of the Iron Triangle. Then the armored personnel carriers and tanks of the 11th Armored Cavalry Regiment plunged west from Ben Cat; the hammer had swung into action."

Throughout the assault, soldiers on the ground continued to discover tunnels, storerooms, cached supplies, and concealed bases used by the Vietcong to sustain their operations throughout the region. Allied forces destroyed them as they were encountered. They met little fierce resistance because most Vietcong simply escaped across the border into Cambodia. As one Vietcong guerrilla later recalled, "For days the Americans besieged him and his comrades in a tunnel, where they barely survived on roots and leaves until, one night, they finally managed to escape."

The fundamental problem for U.S. forces was the severe restrictions on what they could do in neighboring Laos and Cambodia. The rules of engagement were extremely limited, and the Vietcong exploited this by slipping across the border to evade pursuit, then returning as soon as American forces withdrew — which is exactly what happened in the Iron Triangle.

On January 19, soldiers discovered the entrance to an enormous tunnel complex. An Army battalion formed a unit of "tunnel rats" — soldiers armed with .38-caliber pistols fitted with silencers — who entered the tunnels to flush out remaining Vietcong and inspect the network. What they found was staggering. Author Stanton states, "Deep inside the tunnels, caverns opened up to reveal rooms for hospitals, mess halls, munitions factories, and living quarters. What they saw had taken twenty years to build."

It took soldiers six days to inspect the base, which was constructed on four underground levels. During the inspection, they recovered more than forty pounds of documents and maps — including maps showing the locations of U.S. billets in Saigon — indicating extensive Vietcong surveillance operations. Few Vietcong were encountered and only small numbers of soldiers were killed. Ultimately, the tunnel rats who scoured these passages helped establish a specialized unit that was used throughout the country to infiltrate and destroy Vietcong tunnel networks for the remainder of the war.

Some Vietcong remained inside the tunnels; those who did not surrender were shot on sight. There are unverified accounts that patients and nurses were still present in the underground hospital when the tunnels were destroyed. Before entry, tunnel rats would spray tunnel entrances with machine gun fire, and the Vietcong left as guards were typically killed in the barrage.

B-52 bombers and other aircraft provided support for ground troops. In Vietnam: A History, the author notes, "American aircraft bombed its hamlets and denuded its rice fields and surrounding jungles with herbicides before the infantry, accompanied by tanks and bulldozers, moved in to eradicate a reported enemy web of bunkers and tunnels." The operation was officially concluded by January 26, but it did not result in large numbers of Vietcong casualties or captures. One author states, "In Operation Cedar Falls… the U.S. armed forces in effect drove a steamroller over the densely populated area of the Iron Triangle, flattening the villages with five-hundred-pound bombs… and destroying the jungle cover with herbicides."

A French journalist who witnessed the B-52 operations firsthand wrote, "In all my life, I have not heard such a roar. When the B-52s bombard South Vietnam, all of Indochina trembles. Cambodians have declared to me that the tremors reverberate even to Phnom Penh, and that windowpanes rattle there."

The operation officially ended in late January, but even eight months later, the entire Iron Triangle remained under constant bombardment. The danger was so great that an American professor was denied permission to land a helicopter in Ben Suc following an investigation of the area. The military still considered it a "hot" zone, and refugees were not permitted to return to their destroyed villages while military control remained in place.

The U.S. military declared the operation a great success. Author Karnow writes, "The U.S. command hailed the operation as a triumph. But, by the end of the year, the Communists had returned to the devastated region and reconstructed their sanctuary, which they used as a springboard for their assault against Saigon in the Tet offensive of early 1968." This is what makes the operation so significant in Vietnam War history. While it achieved some of its objectives, it displaced thousands of people, destroyed their villages, and the enemy bases were ultimately rebuilt once the Vietcong returned from Cambodia. In that respect, the operation was a failure. Because American forces did not return to the area, the Vietcong quickly reestablished their presence — a presence that contributed directly to the devastating Tet Offensive in Saigon.

Conclusion

Operation Cedar Falls was a momentous event for many reasons. It was the largest ground operation of the Vietnam War, the first time South Vietnamese and U.S. troops formally worked together in a major combined operation, and the first large-scale operation of the conflict. It cleared a vast area of its population and infrastructure, relocating thousands of South Vietnamese from their homes. Yet it was deeply controversial, and it ultimately did not achieve its primary objective: the permanent eradication of the Vietcong threat to Saigon. Because the Vietcong returned to the Iron Triangle and rebuilt their sanctuaries, the operation's enormous human cost — in lives lost, villages destroyed, and communities shattered — yielded no lasting military gain. Today, many people have returned to Ben Suc, but the physical scars from the bombings and bulldozing remain visible throughout the village.