CHAPTER 2

The 3d Marine Division and the Barrier

The 3d Marine Division in the DMZ-The Barrier

The 3d Marine Division in the DMZ

The war in the north was largely the responsibility of the 3d Marine Division. Since the summer of 1966, the division had parried several successive North Vietnamese Army thrusts in Quang Tri Province, both in the northeast and in the west near the Marine base at Khe Sanh. Commanding one of the largest divisions in Marine Corps history, Major General Rathvon McC. Tompkins had more than 24,000 men under him organized into five infantry regiments, one artillery regiment, and supporting elements. U.S. Army artillery units and Navy logistic forces, including Seabees, supplemented the Marines. Two of the regiments of the 1st ARVN Division also reinforced the 3d Division. The division's forward command post was at Dong Ha some eight miles below the Demilitarized Zone. Although one regiment, the 4th Marines, remained in Thua Thien protecting the western approaches to Hue, the bulk of the 3d Division was in Quang Tri Province, mainly facing north, to counter the expected enemy onslaught.

Quang Tri Province contains some 1,800 square miles, extending about 45 miles north and south and 40 miles east and west. Its rugged interior rises to the west with jungled canopied peaks reaching heights of 1,700 meters near the Laotian border. Eastern Quang Tri is characterized by a narrow coastal plain and a piedmont sector of rolling hills. In the north, the Ben Hai River marked the boundary with North Vietnam. The six-mile-wide Demilitarized Zone followed the trace of the river for 30 miles inland and then went in a straight line to the Laotian border. Despite some relaxation of the U.S. rules of engagement in the DMZ south of the Ben Hai, both the Demilitarized Zone and Laos offered a sanctuary for the North Vietnamese Army to mass its forces and position its artillery.

These terrain and political considerations largely determined the enemy's avenues of approach and the 3d Marine Division dispositions in the DMZ sector. The North Vietnamese made their base areas in the Demilitarized Zone and Laos and tried to infiltrate their forces into the river valleys and coastal plain to cut the allied lines of communications. Route l, the main north and south highway, connected the Marine bases of Dong Ha and Quang Tri in the north to Phu Bai and Da Nang further south. The Cua Viet River provided the division its chief logistic artery, running from the Cua Viet Facility at its mouth to Dong Ha. Little more than a mountain path in its western reaches, Route 9 linked Dong Ha with Khe Sanh. Since August 1967, however the North Vietnamese had successfully severed Route 9 west of the Marine outpost at Ca Lu, isolating the Marines at Khe Sanh and permitting resupply only by air.

East of Khe Sanh, the 3d Division was strung out in a series of outposts and bases that allowed protection for Route 9, the important Cam Lo River Valley which extended to Dong Ha, and the coastal plain. The most significant of these were: Ca Lu, 10 miles east of Khe Sanh; the Rockpile, a sheer 700-foot outcropping, eight miles further north; followed by Camp Carroll, 10 miles to the east; and then the heralded 'Leatherneck Square,' the quadrilateral outlined by Cam Lo, Con Thien, Gio Linh, and Dong Ha.

For purposes of delineation and control, the division divided this extensive area into a series of regimental and battalion operational areas with designated code names. For example, the 1st Amphibian Tractor Battalion in Operation Napoleon was responsible for keeping open the Cua Viet waterway. Further north, the 9th Marines, in Operation Kentucky, manned the defenses in the Leatherneck Square sector. In Operation Lancaster, the 3d Marines screened the area from Cam Lo to Ca Lu. Scotland was the code name for the 26th Marines operations at Khe Sanh. To the south, the 1st Marines in Operation Osceola guarded the approaches to the provincial capital and the secondary Marine base near Quang Tri City. The 1st ARVN Division was responsible for the sector east of Route l and south of Dong Ha. With its command post at Dong Ha, the 12th Marines, the artillery regiment, supported all of these operations