The DMZ Campaign (1969–71) was a military campaign by the United States Army, United States Marine Corps (USMC) and the Army of the Republic of Vietnam (ARVN) against the People’s Army of Vietnam (PAVN) along the Vietnamese Demilitarized Zone (DMZ) in northern Quảng Trị Province from 1969 to 1971 during the Vietnam War.
With the departure of the 3rd Marine Division from South Vietnam in late 1969, the U.S. Army expanded its operations along the DMZ until it too was withdrawn in mid-late 1971 when responsibility fell entirely on the ARVN.
Background Prior to 1968 the defense of the DMZ had been the responsibility of the 3rd Marine Division under the control of III Marine Amphibious Force (III MAF) and the ARVN 1st Division. In early 1968 the U.S. Army's 1st Cavalry Division moved to I Corps to conduct Operation Jeb Stuart and to participate in Operation Pegasus, the relief of Khe Sanh Combat Base. On 27 January 1968 COMUSMACV General William Westmoreland ordered the establishment of a new MACV/ARVN headquarters (known as MACV Forward) at Phu Bai Combat Base to control the war in Quảng Trị and Thừa Thiên Provinces. MACV Forward would be commanded by deputy COMUSMACV General Creighton Abrams. The outbreak of the Tet Offensive delayed the establishment of MACV Forward and it would not begin operating until 12 February.
Due to uncertainties regarding the chain of command caused by the establishment of MACV Forward, on 17 February Westmoreland announced that he planned to form a provisional corps in northern I Corps in early March that would consist of the 1st Cavalry Division, the 101st Airborne Division (Airmobile) and the 3rd Marine Division. MACV (Forward) would then be deactivated and the new Provisional Corps, Vietnam under the command of Lieutenant General William B. Rosson would be subordinate to III MAF. Provisional Corps became operational on 10 March. On 15 July XXIV Corps was re-activated to replace Provisional Corps, Vietnam.
On 1 September the U.S. Army's 1st Brigade, 5th Infantry Division (Mechanized) assumed responsibility for the defense of the eastern DMZ from the 1st Marine Regiment as part of Operation Napoleon/Saline. With the conclusion of Operation Napoleon/Saline on 9 December 1968, the Napoleon/Saline operational area was absorbed into the Operation Kentucky operational area under the control of Marine Task Force Bravo.
At the beginning of 1969 XXIV Corps comprised the 101st Airborne Division (Airmobile) in Thừa Thiên Province and the 1st Brigade, 5th Infantry Division (Mechanized) responsible for the coastal lowlands of Quảng Trị Province while the 3rd Marine Division remained responsible for the highlands of western Quảng Trị Province. Operation Kentucky concluded on 28 February 1969.
Operation March 1969 On 1 March at 10:50 the armored cavalry squadron of the 1st Brigade, 5th Infantry Division engaged a PAVN force northwest of Cam Lộ District, killing 33 PAVN; U.S. losses were two killed. On 3 March at 03:00 a Marine firebase north of the Rockpile occupied by a unit of the 4th Marine Regiment was attacked by the PAVN. The attack was repulsed with 20 PAVN killed and 10 individual weapons captured; U.S. losses were 13 killed.
On 7 March at 15:00 a company from the 1st Brigade was attacked south of Quảng Trị, the company returned fire and directed artillery onto the area, resulting in ten PAVN killed and two captured; U.S. losses were four killed. At 16:15 an aerial observer saw 100 PAVN in fortified positions northeast of Con Thien and directed artillery fire onto the positions, destroying five bunkers and killing seven PAVN. On 8 March at 10:00 infantry from the 1st Brigade found graves containing ten PAVN/Vietcong (VC) dead south of Quảng Trị, all had been killed ten days previously. On 9 March at 11:00 a patrol from the 3rd Marine Regiment ambushed a PAVN platoon south of Cam Lộ. The Marines called in artillery fire and killed 20 PAVN and captured one and 13 individual and one crew-served weapons.
On 11 March at 16:15 an aerial observer saw 15 PAVN north of Con Thien and called in artillery fire, killing ten. At 17:30 an aerial observer received fire 3 miles west of Con Thien and called artillery fire onto the position, killing four PAVN and destroying three .51 cal machine guns. On 13 March at 11:15 a unit of the 4th Regiment engaged a PAVN force northwest of the Rockpile, the action continued until 08:00 the next morning when the PAVN withdrew, leaving 23 dead; U.S. losses were ten killed. On 15 March at 06:00 15 122/140 mm rockets hit Cửa Việt Base. A Forward Air Controller (FAC) saw the firing position northeast of Gio Linh and directed artillery and naval gunfire onto the location, causing a secondary explosion. A Marine patrol moved to the firing location and engaged a PAVN force northeast of Gio Linh. The Marines were reinforced by amphibious vehicles at 07:30 and the battle continued until 10:40 when the PAVN withdrew, leaving ten dead and two captured and one 82 mm mortar.
On 16 March at 02:15 a Combined Action Platoon (CAP) operating north-northwest of Đông Hà was attacked by a PAVN company, the PAVN then withdrew to the northwest. As the patrol was returning to their base they were attacked again. U.S. losses were five killed and four Vietnamese civilians were killed. On 17 March at 17:00 a forward observer located newly constructed bunkers northeast of Gio Linh and directed naval gunfire onto the location, causing nine secondary explosions and destroying ten bunkers. On 23 March at 22:30 a Marine forward observer reported a PAVN force moving northwest of The Rockpile and directed artillery fire onto the location, causing nine secondary explosions. From 23 March to 3 April the 1st Brigade conducted Operation Montana Mauler near Firebase Fuller. On 24 March at 18:00 an armored cavalry unit of the 1st Brigade engaged a PAVN force northeast of the Rockpile, killing 23 PAVN.
On 25 March at 10:00 a unit of the 9th Marine Regiment engaged a PAVN force west of Cam Lo killing seven PAVN. At 16:00 the same unit encountered another PAVN force, killing a further four; U.S. losses were one killed. On 27 March at 10:00 infantry from the 1st Brigade patrolling northwest of Cam Lộ engaged a PAVN force. The unit was supported by armor, artillery, helicopter gunships and airstrikes and the PAVN withdrew at 18:30, leaving 120 dead and seven individual and three crew-served weapons; U.S. losses were 14 killed. On 28 March at 10:00 infantry from the 1st Brigade engaged an entrenched PAVN force northwest of Cam Lộ. The unit was supported by artillery and tactical airstrikes, causing four secondary explosions. The PAVN withdrew at 18:30, leaving 68 dead and 16 individual weapons; U.S. losses were one killed. On 29 March at 08:30 an aerial observer received fire north-northeast of Gio Linh and directed artillery onto the firing position, resulting in three secondary explosions and destroying four structures and killing one PAVN.
April Operation Montana Mauler concluded on 3 April with 271 PAVN killed and 23 individual and six crew-served weapons captured; U.S. losses were 38 killed.
May On 1 May at 07:00 a unit of the 3rd Marine Regiment engaged a PAVN force northwest of the Rockpile. The PAVN withdrew at 16:00, leaving seven dead and one individual and one crew-served weapons; U.S. losses were seven killed. At 16:40 an aerial observer saw a bunker complex northeast of Gio Linh and directed airstrikes onto the location which caused a secondary explosion and destroyed four bunkers. On 2 May at 09:15 a Marine CH-46 collided with an Army UH-1 while taking off from a landing zone northwest of the Rockpile, killing all 12 marines on board. At 14:25 an aerial observer saw PAVN near bunkers north of Gio Linh and directed artillery fire onto the position, resulting in two secondary explosions and killing two PAVN.
On 3 May at 13:45 an aerial observer saw PAVN near a bunker complex north-northeast of Gio Linh and called in artillery fire and airstrikes on the position, destroying four bunkers and killing four PAVN. At 20:40 a forward observer saw lights moving northwest of the Rockpile and directed artillery onto the position, causing ten secondary explosions. On 4 May at 16:55 an aerial observer saw a bunker complex north-northeast of Gio Linh and directed artillery fire onto the position, causing five secondary explosions. On 5 May at 18:20 an aerial observer received fire west-southwest of Con Thien and directed artillery and airstrikes onto the firing position, causing three secondary explosions and destroying eight bunkers.
On 6 May at midday an aerial observer saw six PAVN near a bunker complex west-southwest of Con Thien and directed artillery fire onto the position, destroying a bunker and killing five PAVN. At 16:30 an aerial observer received fire northwest of Gio Linh and directed artillery fire onto the position, causing one secondary explosion and destroying nine bunkers. The bodies of six PAVN were seen in the strike area. On 8 May at 08:30 a unit of the 3rd Marine Regiment patrolling north-northeast of the Rockpile engaged a PAVN squad in bunkers. The Marines attacked supported by artillery and the PAVN withdrew, leaving five dead; U.S. losses were two killed. At 11:00 an aerial observer received fire north-northwest of the Rockpile and directed artillery fire onto the firing position. On 9 May at 15:35 an aerial observer saw 15 PAVN moving north-northwest of the Rockpile and called in artillery fire, causing three secondary explosions and killing three PAVN.
On 10 May at 04:15 a unit of the 3rd Marine Regiment in a night defensive position north of the Rockpile received a ground probe. The Marines returned fire and were supported by AC-47 Spooky gunships forcing the PAVN to withdraw; U.S. losses were eight killed. At 09:45 an aerial observer saw 40 PAVN on a trail south-southwest of Quảng Trị and directed artillery and airstrikes onto the area, killing 27 PAVN. On 11 May at 17:35 an aerial observer saw PAVN west-northwest of Con Thien and directed artillery and airstrikes onto the area, killing 19 PAVN. On 12 May between 02:30 and 18:30 the PAVN fired mortars and rockets at U.S. bases near Gio Linh, the Rockpile and Con Thien. Naval gunfire was directed onto the firing positions, causing ten secondary explosions. At 17:40 a forward observer saw five PAVN moving north-northeast of Con Thien and directed artillery fire onto the position, causing a secondary explosion and killing three PAVN.
On 13 May at 15:05 a unit of the 3rd Marine Regiment in a position west-southwest of Con Thien received 15 82 mm mortar rounds, causing no damage, and directed artillery fire onto the firing position, resulting in one secondary explosion. At 17:40 a forward observer saw five PAVN north-northeast of Con Thien and directed artillery fire onto the position, causing a secondary explosion and killing three PAVN. On 15 May at 11:50 an aerial observer saw six to eight PAVN west-southwest of Con Thien and directed artillery fire onto them and five PAVN dead were seen in the strike area. On 16 May at 23:40 a Marine reconnaissance unit engaged a PAVN platoon northeast of Dong Ha, the battle continued sporadically until 05:30 on 17 May with the PAVN losing eight killed and one individual weapon captured.