The mission of Operation Dewey Canyon was clear — disrupt and destroy enemy logistics in the A Shau Valley, particularly in the NVA’s Base Area 611. As described by Samuel Lipsman and Edward Doyle in Fighting for Time, part of Boston Publishing Company’s multivolume Vietnam Experience, Base Area 611 “straddled the Vietnamese-Laotian border just north of the A Shau Valley and south of the Da Drong River….More than three-quarters of the base area was believed to lie in Laos, along Route 922. This route later joined Route 548 to provide easy access for the NVA into the Da Nang-Hue coastal region.”

Subscribe Today

• Did you enjoy our article?
• Read more in Vietnam Magazine
• Subscribe online and save nearly 40%!!!
 

NVA engineering units, inactive for months, had reopened several major infiltration routes. This included increased enemy activity along Route 922 as it enters the A Shau Valley in the Republic of South Vietnam from Laos. The intelligence reports brought additional scrutiny on the border areas. Enemy forces laid down heavy volumes of anti-aircraft fire against U.S. Helicopters and other responding high-performance reconnaissance aircraft. Surveillance reported sightings of sophisticated wire communications networks and major engineering works throughout Base Camp Area 611 with, at times, more than 1,000 trucks per day on the move south.

Evidence strongly indicated that major elements of the 6th and 9th NVA regiments were attempting to work their way eastward through the A Shau Valley. There they could be reinforced by three battalions of the 812th Regiment, which after the Tet Offensive of 1968 had pulled back into the jungle sanctuary on the border for resupply and infusion of replacements, and by elements of the 4th and 5th NVA regiments, which had withdrawn into the A Shau Valley and Laos under constant U.S. and ARVN pressure during 1968.

It seemed obvious that the NVA intended to launch a Tet offensive of some kind in 1969, although probably not of the devastating magnitude of the 1968 Tet. Any form of victory, even one of minor or only temporary tactical value, could have a significant influence upon the civilian population of South Vietnam and the United States, with a more far-reaching effect upon bargaining positions at the Paris peace talks then underway. The enemy’s jungle logistics system would therefore have to be destroyed before it could be used.

No longer content to simply hold ground and fight insurgent forces within South Vietnam, U.S. commanders decided that it was time to take the battle to the North Vietnamese Army. To address the threat of a North Vietnamese invasion from Laos they would strike at NVA headquarters and logistics elements in the border areas, thereby denying the enemy access into the critical populated areas of the coastal lowlands of Quang Tri, Thua Thien and Quang Nam provinces.

General Creighton Abrams, the MACV commander, wanted an operation to be conducted during the winter period of 1968-69, believing that it had great tactical promise in advancing the issues of the war. General Raymond G. Davis, the 3rd Marine Division commander, had discussed such an operation with General Richard Stilwell, XXIV Corps commander.

It would not be easy, for the enemy had chosen the site of their base camp well. The terrain in the A Shau Valley was as inhospitable and formidable as any in Vietnam.

Because of its experience operating in the rugged mountains and thick jungle canopy of western Quang Tri province, the U.S. 9th Marine Regiment was selected to conduct Operation Dewey Canyon. The men of the regiment were mentally and physically prepared for the rigors of Dewey Canyon’s terrain. They brought to the operation experience in jungle survival and landing zone construction, as well as skills in the conduct of mountain warfare, including heliborne operations and the fire support base concept.

During the five-day planning period allowed for the operation, an XM-3 Airborne Personnel Detector picked up evidence of enemy troop concentrations atop a 2,100-foot-long ridgeline 4 1/2 miles from the Laotian border which would be developed into Fire Support Base Cunningham, the eventual command center for the operation.

Help HistoryNet by bookmarking to