The Mu Gia pass, a gap in the Truong Son (Annamite) Mountains that formed North Vietnam’s border with Laos, is one of two northern entry points to the Ho Chi Minh trail. To the east, the pass is flanked by a peak of 6,600 feet and on the Laotian side to the west, with a series of mountains in the 4000-4500 foot range. Mu Gia crosses the cordillera at slightly under 1400 feet, making it one of the few passable spots along the rugged Truong Son range. Mu Gia was strategically located some 75 miles as the crow flies from the border of South Vietnam; 80 miles from Tchepone, the site of an airfield with a 4000-foot-by-65-foot runway; 100 miles from the Ban Houei Sane border area, and some 250 miles from vital supply points in the Central Highlands.
Because of its geographic and strategic importance, Mu Gia became a focus of numerous intelligence-gathering missions by “tiger teams” of agents or commandos whose mission it was to penetrate North Vietnam and come up with new data on the trail. By the spring of 1964, the Pentagon was carrying out active target studies, including specific lists of Trail targets and notations of how many sorties would be required to neutralize them. For the Mu Gia pass, the JCS estimated in 1964 that 14 aircraft sorties would be sufficient to neutralize the area. This estimate proved to be highly optimistic.
Navy planes from the USS Coral Sea made the first interdiction strike on the Mu Gia Pass on February 28, 1965. There were 10 Navy A-1H Skyraiders and 14 A-4c Skyhawks, accompanied by two photo planes. The planes dropped bombs that ranged from 500 to 2000 pounds, some set to detonate as long as six days later. The following week, US interdiction targets again included Mu Gia and on March 21, planes from the carrier Hancock struck the Laotian side of the pass. In the summer of 1965, the pass once more appeared on the list of bombing targets. On July 16 and 17, F-105 fighter-bombers dropped 18,000 pounds of munitions on Mu Gia.
Mu Gia and other strategic spots along the Ho Chi Minh trail became a struggle between American attempts to shut down the supply route and Vietnamese ones to keep them going. Defending the route was a core of committed laborers, who protected the trail by making it physically hard to bomb. Over the short term, this meant that the trail was maintained by guerrilla warfare standards, composed of narrow passageways — ranging from a mere six to eight feet wide. Although this limited the transfer of supplies to pack animals and bicycles, it made the area a more difficult target for bombing. Over the long term, Hanoi made preparations for widening parts of the trail to accommodate guns and trucks, which eventually increased the systems supply capacity and allowed the North Vietnamese to respond militarily to US aircraft.
The bombing of Mu Gia continued through the winter, spring, and summer of 1966. According to a May 6, 1966 Time magazine article, during one week-long series of sorties, Guam-based B-52s unloaded 300 tons of high explosives on the pass. The attacks continued through December 1966, maximum-effort strikes using thirty or more huge bombers. It became a very bloody business, and a very considerable number of US aircraft went down along the Trail. According to several POW-MIA sites, between 1965 and 1971, 43 American airmen were shot down over the Mu Gia pass alone.