The base was established 13 km north of Đông Hà on Highway 1 immediately south of the Vietnamese Demilitarized Zone. On 19 May 1966 the People's Army of Vietnam attacked the ARVN base at Gio Linh killing 43 and wounding 54. From 15–18 September 1966 the 1st Battalion, 26th Marines launched Operation Deckhouse IV and discovered that the PAVN had built a network of tunnels and bunkers in the Con Thien-Gio Linh area. Gio Linh was intended to form part of the McNamara Line and formed one corner of what became known as Leatherneck Square, with the other corners being Con Thien, Cam Lộ Combat Base and Đông Hà Combat Base. In February 1967 the 12th Marines had 4 175mm guns and 6 105mm howitzers based at Gio Linh. On 27 February the PAVN attacked Gio Linh with mortars, rocket and artillery fire. On 20 March the base was subjected to another rocket and artillery attack and on 21 March a supply convoy was ambushed just 300m from the base. The PAVN claimed to have killed over 1,000 enemy troops and destroyed 17 artillery pieces, 57 vehicles and three helicopters in the 20 March artillery barrage. From 20 March to 1 April Operation Beacon Hill saw BLT 1st Battalion, 4th Marines patrolling around the base to try to prevent further PAVN attacks. From 10–17 April the 11th Engineer Battalion began clearing a 200m wide strip between Gio Linh and Con Thien, a distance of over 10 km the strip was eventually completed on 1 July and widened to 600m. On 27/8 April Gio Linh was hit by over 800 artillery shells and 200 mortar rounds. On 8 May the PAVN launched an attack on Con Thien and shelled Gio Linh in an attempt to reduce its fire support for Con Thien. On 17/18 May PAVN artillery rockets and artillery hit Đông Hà and Gio Linh, killing 1 Marine and wounding 12 others at Gio Linh. By July engineers had completed clearing a 500m radius around the base and had started building underground bunkers. On 2 July, the first day of Operation Buffalo the base was again heavily shelled in an attempt to reduce fire support for the encircled 1st Battalion, 9th Marines.
In 1970 the M55 Self Propelled Howitzer of the Marines 5th 175mm Gun Battery remained at Gio Linh under the command of the Army's 108th Artillery Group. A small number of Marines remained at Đông Hà as part of the ANGLICO unit supporting the ARVN 1st Division. By January 1972 the ARVN 3rd Division had assumed responsibility for the area north of Highway 9. The PAVN launched their Easter Offensive on 30 March 1972 and by midday on 1 April the ARVN garrison at Gio Linh had retreated from their perimeter positions to the base's bunkers, while the 5-man ANGLICO team continued to call in fire missions against the advancing PAVN. PAVN forces were probing the base perimeter when an Army Bell UH-1 Iroquois arrived to evacuate the ANGLICO team, just as the team was boarding the helicopter the landing zone was hit by mortar fire mortally wounding the team leader. Corporal James Worth of the ANGLICO team failed to board the helicopter and was listed as Missing in Action. By nightfall on 1 April all ARVN defensive positions along the DMZ and north of the Cam Lo River had fallen to the PAVN. Gio Linh would remain in North Vietnamese hands for the rest of the war.
