On the morning of July 2, 1967, Bravo and Alpha Companies of the 1st Battalion, 9th Marines — the regiment that would earn the nickname "The Walking Dead" before the war ended — moved north from Con Thien toward the Ben Hai River. Their mission was a routine sweep: locate and engage North Vietnamese Army forces operating near the Demilitarized Zone. By mid-morning they had located them.

The NVA unit waiting in prepared positions was the 90th Regiment of the 324B Division, a formation that had crossed the DMZ in force and established a network of fortified positions across the open scrubland north of Con Thien. What followed was not a meeting engagement but an ambush — the NVA surrounded the lead Marine elements and opened fire from multiple directions simultaneously.

The Tactical Situation at Con Thien

Con Thien — "the Hill of Angels" in Vietnamese — was a 158-meter rise in Quang Tri Province, two miles south of the DMZ. By the summer of 1967, it had become one of the most contested pieces of ground in the war. Its elevation gave observers a line of sight into the DMZ itself, making it valuable for directing fire against NVA infiltration routes. The NVA recognized this and subjected Con Thien to sustained artillery fire throughout 1967, earning it the description by Marine veterans as "the meat grinder."

The 3rd Marine Division's tactical approach in this period was to push patrols aggressively north and northwest of Con Thien to interdict NVA movement. These patrols operated under the rules of engagement that prohibited ground combat north of the DMZ but permitted fire missions there. The result was that Marine ground units operated in an area increasingly dominated by NVA forces that could prepare positions and retire across the line as needed.

Operation Buffalo — officially authorized July 2, 1967, in response to intelligence indicating a large NVA force south of the river — was a battalion-level effort to fix and destroy that force. The intelligence was accurate. The NVA was there, in strength, and waiting.

July 2: The Ambush

Alpha Company, 1/9 Marines, made contact first, approximately 1,500 meters north of Con Thien. The contact was immediately violent: the NVA opened with mortars, RPGs, and small-arms fire from three sides. Bravo Company, moving to reinforce, was hit on its flanks as it closed the distance.

Within the first hour of the engagement, both companies had sustained heavy casualties and lost coherent command structure at the platoon level. Captain Sterling K. Coates, commanding Alpha Company, was killed early in the fighting. Radio communication with the battalion command post at Con Thien was intermittent, disrupted by NVA jamming and terrain.

Reinforcement was attempted by Delta Company, which fought through significant contact to reach the engagement area. Artillery support from Con Thien and naval gunfire from ships offshore was called in, but accurate delivery in close proximity to intermixed forces was difficult. Air support was requested but weather initially limited effectiveness.

"It was the worst day I ever saw in Vietnam," Corporal Dennis Smith of Bravo Company told combat historian Al Hemingway years later. "We were surrounded and taking fire from everywhere."

By nightfall on July 2, 1/9 Marines had suffered approximately 84 killed and over 190 wounded in the initial day's fighting — one of the highest single-day casualty counts in Marine Corps history to that point in the war.

The Operation Continues

Operation Buffalo ran from July 2 through July 14, 1967. In the days following the initial ambush, the 3rd Marine Division committed additional battalions to the area north of Con Thien. The fighting remained intense: the NVA 324B Division was a well-equipped, highly trained formation with established logistics support from across the DMZ.

The Marines systematically cleared NVA positions with a combination of artillery preparation and infantry assault. The close terrain — elephant grass, scrub, and abandoned rice paddies — favored defensive positions and made movement costly. Marine casualty rates remained high throughout the operation.

By the time Operation Buffalo was officially concluded on July 14, the 3rd Marine Division reported 1,281 NVA killed and 3 captured. US Marine casualties for the operation totaled 159 killed and 345 wounded. The 1st Battalion, 9th Marines alone lost over a quarter of its effective strength in the first 48 hours.

Strategic Context and the McNamara Line

Operation Buffalo took place against the backdrop of an ongoing debate at the highest levels of the US military and civilian leadership about strategy along the DMZ. General William C. Westmoreland's approach — search and destroy operations to attrite NVA forces — was producing high enemy casualty counts but was also generating Marine losses that strained the regiment's manpower.

The alternative being promoted by Secretary of Defense Robert McNamara was the construction of a barrier system across the DMZ — a combination of cleared ground, sensor fields, and fortified strong points that would reduce the need for aggressive patrolling. The Marines on the ground were deeply skeptical. Operations like Buffalo demonstrated that the NVA could cross the DMZ in strength and concentrate for ambushes faster than a static barrier could detect and respond.

The barrier system, dubbed the McNamara Line, was partially constructed but never fully operational. The siege of Khe Sanh in 1968 and the Tet Offensive rendered the DMZ strategy moot in any case.

The Marines of the 1st Battalion, 9th Marines who fought at Con Thien in July 1967 had no way of knowing any of this. They knew that on July 2 they had walked north and walked into something that killed a great many of their friends before it was over. Operation Buffalo is not well remembered outside the Marine Corps. It should be.