Written by Major General David Ewing Ott

The 66 day battle of Khe Sanh, which began in January 1968 became a classic defensive operation for US Forces. It tested American concepts of defense and demonstrated that good fire support could effectively neutralize a superior force.

Khe Sanh sits atop a plateau in the shadow of the Dang Tri Mountains and overlooks a tributary of the Quang Tri River. Surrounding it on all sides are hills from which the North Vietnamese could shell the base. If controlled by the Marines, however, the hills would form a ring of protection for the base and afford good vantage points for detecting enemy movement. American involvement at Khe Sanh had begun in 1962, when Special Forces elements established a Civilian Irregular Defense Group camp at the site that was later known as the Khe Sanh Combat Base. Its purpose was to counter enemy infiltration through the area and provide a base for surveillance and intelligence-gathering operations in the western part of Northern I Corps. Marine units occupied the base in late 1966 and the Special Forces moved southwest to the village of Lang Vai.

Between late 1966 and late 1967, activity around the base fluctuated from heavy contact to none at all. Then in December 1967 a surge of enemy activity began. Reconnaissance teams reported large groups of North Vietnamese moving into the area.

NVA presence in the Khe Sanh area increased; Khe Sanh was the nest from which the hornets stung them in Laos. (Gen. Giap was always interested in the area. He had been imprisoned at the prison at the D'Ai Lao, known as Lao Bao, 19301932 along with his brother Nho, a prison so harsh that prisoners rarely returned from it).

Contacts became more frequent. On 18 Jan '67, Cpl Michael John Scanlon of the 3d Force Recon Co Det became the first USMC KIA at Khe Sanh. As a result of a contact 26-27 Jan, 4 USMC helicopters were lost. BN 1/9 arrived at Khe Sanh on 6 Feb '67 and made contact 25 Feb just 1500 meters west of the airstrip. Force Recon patrols reported significant NVA presence. On 16 Mar, the newly arrived E/2/9 made contact in which 18 Marines were KIA.

USAF pilots of TIGERHOUND reported: "an alarming buildup of fortifications and NVA activity on the hills overlooking the base."

Yet, the base commander was convinced there was little or no NVA presence or activity.

Casualties for 24 Apr were: 14 USMC KIA, 18 WIA, and 2 MIA, 5 NVA KIA (confirmed) and 100 KIA (probable). Support for 24 Apr: 660 rounds of 105mm and 8 fixed wing SORTIEs dropping 6500 pounds of ordnance.

The movement in itself was not irregular, but now the forces were staying, not passing through. The enemy was building up men and equipment in preparation for a siege. The enemy initiated major offensive action around Khe Sanh early in January 1968, when he shifted his emphasis from reconnaissance and harassment to actual probes of friendly positions.

On the night of 2 January an outpost at the western end of the base reported six unidentified figures walking the around outside the wire. When challenged, they made no reply and were taken under fire. Five of the six were killed. Later investigations disclosed that the dead included a North Vietnamese regimental commander and his operations an communications officers. The commitment of these key men to such a dangerous reconnaissance mission was a clear indication that something big was going to happen.

In the predawn hours of 21 January, the enemy began his anticipated move against Khe Sanh. Just after midnight rockets and artillery shells began impacting on Hill 861 to he northwest of the city. A full scale ground attack followed, only to be repulsed after several hours of fighting. NOTE (The 175’s of the 2/94^th on Camp Carroll along with the tenacity of the Marines on the hill repulsed two attacking battalion’s of NVA Regulars.) At 0530 another intense barrage of 82mm shells and 122mm rockets hit Khe Sanh. Damage was substantial: a major ammunition dump and fuel storage area was destroyed.

When the news of the attack reached the United States, many questioned the feasibility of defending Khe Sanh. The base was isolated and with Route 9 interdicted, would have to be resupplied by air. Fearing Khe Sanh would become an American Dien Bien Phu, critics favored a pullout.

The problem, therefore, was not merely how to defend the base but whether the base should be defended at all. General Westmoreland and General Cushman, commander of the III Marine Amphibious Force, decided to defend Khe Sanh. The base and adjacent outposts commanded the plateau and the main avenue of approach into eastern Quang Tri Province. Although these installations did not stop infiltration, they blocked motorized supply from the west. Another advantage of holding the base was the possibility of engaging and destroying a heretofore elusive foe. At Khe Sanh, the enemy showed no desire to hit and run but rather chose to stand and fight. The Marines could fix him in position around the base while air and artillery barrages closed in. Finally, two crack North Vietnamese divisions, which might have participated in attacks in other areas of South Vietnam, were tied down by one reinforced Marine regiment. The decision made, all that remained was to complete the buildup of men and material required to hold the base.

Air power and artillery played an important role at Khe Sanh and were given the highest priority. The Khe Sanh defenders had three batteries of 105mm hoitzers, one battery of 4.2 mortars, and one battery of 155mm howitzers: all five batteries were Marine artillery. In addition, they were supported by four batteries of Army’s 2^nd Battalion 94^th Artillery 175mm guns, one at the Rockpile , north of the base, and three at Camp Carroll, to the east.

These artillery pieces, 46 in all, were supplemented by 90mm tank guns, 106 recoilless rifles and tactical air support. The fire support coordination center , the 1^st Battalion, 13^th Marine Artillery located at Khe Sanh, controlled all supporting arms fire. Once the fighting began, the battalion commander, LTC Lownds, said that the side which keeps its artillery intact will win the battle. Only three American artillery pieces were destroyed during the entire siege.

Since the enemy maneuvered mainly under the cover of darkness, the Marine and Army batteries were most active during these hours. Pre-planned artillery fires included combined time-on-target fires from nine batteries, separate battalion time-on-target missions, battery multiple-volley individual missions, and battery harassment and interdiction missions. Fire support coordination progresses to the point that artillery was seldom check fired while tactile aircraft were operating in the area. Throughout the battle 158,981 rounds of various caliber of artillery were directed against enemy locations around the base.

During the siege, air-delivered fire support reached unprecedented levels. A daily average of 45 B 52 sorties and 300 tactical air sorties struck targets near the base. Eighteen hundred tons of ordnance a day laid waste wide swaths of jungle terrain and caused hundreds of secondary explosions. In seventy days of air operations, 96,000 tons of bombs, nearly twice what the Army Air Corps delivered in the Pacific during 1942 and 1943, pulverized the battle area.

In addition to volume reaction time was a key factor. Relatively easy clearance procedures meant immediate response-unless friendly aircraft were in the target area - regardless of the weather. Artillery rounds were usually on the target area within forty seconds after the call for fire. This instant artillery response impaired enemy movements within the tactile area of responsibility and helped to break up numerous attacks.

Protective fires were carefully planned in advance. The fires from the artillery batteries planned by the fire support coordination center prevented the enemy assault forces from reaching the perimeter wire. Because the North Vietnamese usually attacked with their battalions in column, the center also planned fires to isolate the assault elements form the reserves. When the enemy launched his attack, the center placed a three-sided artillery box around the lead enemy battalion. Three batteries of the 1^st Battalion, 13^th Marines executed this mission. The fourth battery then closed the remaining side, which faced the friendly positions, with a barrage that rolled from one end of the box to the other much like a piston within a cylinder. The enemy force in the box could neither escape or avoid the rolling barrage. Those Vietnamese who spilled out of the of the open end of the box came under the final protective fires of the marines along the perimeter. At the same time, the fire support center placed a secondary box around the North Vietnamese backup units. The four 175mm batteries of the 2/94^th were responsible for the two sides, which were 500 meters outside the primary box. On order, the gunners rolled their barrage in toward the sides of the primary box and back out again. The third side was sealed by continuous flights of aircraft under the control of the radar. When ever B-52’s were available or could be diverted in time, arc lights saturated the approach routes to the battle area.

With the 1^st of the 13^th Artillery cutting the middle of the formation and two sides. The 2/94^th outside 13^th sides would roll towards the sides of the 105mm and 155mm fire lines closest to the Marine lines. Then in behind were the formation had been cut by the 13^th the 2/94^th would then roll all the way across ensuring that any reserve units for a secondary attack were also neutralized. In behind the 175mm fires the air support would have cut off any means of retreating along the same line of march originally initiated.

The manner in which the center coordinated its air and artillery support was another critical element in the defense of Khe Sanh.

The mini arc light, devised by the assistant fire support coordinator, was used against area targets.. The mini arc light was similar to a B 52 strike but could be organized and employed more rapidly. When intelligence reports indicated the enemy units were in a certain region, the fire support coordination center plotted a 500 by 1,000 meter block in the suspected area or across a likely route of march. Then the center called two Intruder tactile aircraft, each armed with twenty-eight 500 pound bombs, for a radar bomb run. Meanwhile the batteries at Khe Sanh, Camp Carroll, and the Rockpile were alerted for a fire mission. Thirty seconds before the bombs were dropped, the 175mm batteries of the 2/94^th concentrating their fires on one-half of the block, salvoed the first of approximately 60 rounds. When the aircraft rippled their loads down on the middle of the block, the Marine Artillery batteries opened up on the second half with about 200 155mm, 105mm and 4.2 inch rounds. The trajectory and flight times of all ordnance were computed so that the bombs and initial artillery rounds hit at the same instant. The saturation of the target area all but insured that any enemy soldier caught in the zone during the bombardment would be a casualty.

The micro arc light, developed and executed in the manner of the mini arc light, used less ordnance and covered a 500 by 500 meter target block. The advantage of the micro arc light was that it could be in effect within ten minutes whereas the mini arc light required roughly 45 minutes. On an average night the fire support center executed three to four mini arc lights and six to eight micro arc lights.

Marine/Army Artillery also functioned extensively in the direct fire role on an as needed basis.

On 31 March, the 1^st Cavalry Division took control of the 26^th Marine Regiment, signaling the start of Pegasus, a fifteen-day air assault operation that ended the battle of Khe Sanh. The 1^st Cavalry Division , along with the 1^st Marine Regiment ad South Vietnamese 3 Airborne Task Force, began a push form Ca Lu, located east of Khe Sanh , to reopen Route 9 and relieve the pressure on Khe Sanh. The siege, in effect, was over.

The base plan of Operation Pegasus called for the 1^st Marine Regiment, with two battalions to attack west toward Khe Sanh while the 1^st Cavalry Division air assaulted onto the high ground on either side of Route 9 and moved constantly west toward the base. On D plus 1 an D plus 2, all elements would continue to attack west toward Khe Sanh. Then on the following day the 2d Brigade of the 1^st Cavalry Division would land three battalions sootiest of Khe Sanh and attack northwest. The 26^th Marine Regiment, holding Khe Sanh would attack south to secure Hill 471. The linkup was planned for the end of the seventh day.

Fire support involved a multitude of units, requiring detailed planning and coordination for the two phases of the operation - reconnaissance and attack. The objective of the reconnaissance phase was the destruction of the enemy antiaircraft resources between Ca Lu and Khe Sanh and the selection of the landing zones for use by the advancing airmobile assault forces. The 1^st squadron, 9^th Air Cavalry, assumed this mission and was supported by an abundance and artillery. Additional artillery was moved onto the area during the reconnaissance phase and automatically came under the control of a forward division artillery fire direction center located at Landing Zone Stud and manned by personnel of the 1^st Battalion, 30^th Artillery. The additional artillery included one Marine 4.2 inch mortar battery at Ca Lu and two 105mm batteries (one Marine and one Army) at the Rockpile. On 25 March an 8 inch battery and a 105 battery moved from Quang Tri to Ca Lu and Stud respectively. This move brought the total to 15 firing batteries available to support the 1^st Squadron, 9^th Air Cavalry, in its reconnaissance. All batteries in the area began answering calls for fire form the 1^st Squadron, 9^th Cavalry, on D minus 6 and commenced attacking planned targets that night. Prior coordination between the 3rd Marine Division: the 108^th Artillery Group (included the 2/94^th at Carroll and the Rockpile); and the 1^st Battalion, 13^th Marines (Artillery), insured that all available target information would be in the hands of the forward fire direction center and lateral communication would be established. Throughout this phase, air and artillery fire destroyed enemy automatic weapon, mortars, and troop positions.

The attack phase consisted of the preparation of landing zones, suppression for enemy fires, and on-call support of committed ground forces. For the attack phase ten 105mm howitzer batteries, four 155mm howitzer batteries on 8 inch howitzer battery, and on 4.2 inch mortar battery joined the already overwhelming artillery force. Each cavalry brigade had reinforcing fire from a medium battery, and the 1^st Marine Regiment could count on support from two 105mm batteries, one 155mm battery, and one 4.2 inch battery. The additional heavy battery with the mission of general support of the 1^st Air Cavalry Division moved from Camp Evans to LZ Stud. Thirty one firing batteries supported the relief of Khe Sanh ---- the largest array of artillery ever to support a single operation in Vietnam to that time.

Counterbattery fire contributed significantly to the success of Operation Pegasus. For some time, North Vietnamese forces has been able to shell Khe Sanh at will with 152mm and 130mm artillery plus rockets and mortars positioned to he southwest and northwest of the base. When the 1^st Cavalry Division Artillery came within range of the enemy guns, rapid and massive counterbattery fire achieved superiority. From that point enemy artillery ceased to be a serious deterrent to maneuver.

On 6 April at 1350, six days after Operation Pegasus had begun the initial relief of Khe Sanh took place. A lead company of the South Vietnamese 3^rd Airborne Task Force airlifted into Khe Sanh and linked up with the South Vietnamese 37^th Rangers. Two days later the 2^nd Battalion, 7^th Cavalry, had completed its sweep along Route 9 and the official relief took place. The command post of the 3 Brigade, 1^st Cavalry, airlifted to the base at 0800 and became its new landlord. By the evening of 8 April, all elements of the task force were in position on the Khe Sanh plateau. The North Vietnamese 304^th Division faced entrapment and destruction as a great vise closed about the enemy daily. American and South Vietnamese units soon uncovered grisly evidence of how badly the North Vietnamese had been beaten. They found hundreds of North Vietnamese bodies in shallow graves and hundreds more that lay where they had fallen. The allies destroyed of captured 557 individual weapons, 207 crew served weapons and to antiaircraft pieces. In addition they confiscated 17 vehicles ranging from PT76 tanks to motor scooter, tons of ammunition and food, and numerous radios and items of individual equipment. The mountain of abandon enemy stores indicated either that Pegasus had caught the enemy flat footed or that the remnants of the enemy divisions had been unable to cart off their equipment and supplies.

On the morning of 14 April, Pegasus officially ended. The operation was successful, Rote 9 opened, the enemy routed, and the base itself relieved. The North Vietnamese lost 1,304 killed and 21 captured. The battle of Khe Sanh established that, with sufficient fire power, an encircled position could be successfully held and the enemy devastated.

Final Statistics for the Defense of Khe Sanh

U.S. & Allied Casualties

730 Americans Killed in Action
2,642 Americans Wounded in Action
7 Americans Missing in Action
229 South Vietnamese ARVN Killed in Action
436 South Vietnamese ARVN Wounded in Action