Viet Cong tunnels

Just 40 kilometres from Saigon, around an area known as the Iron Triangle in the Cu Chi district, lay the most complex Viet Cong tunnel system in South Vietnam. The area, a Viet Cong stronghold, was heavily defended and used as a base for attacks on the South Vietnamese capital, Saigon. The most extensive of the tunnel systems, which covered some 400 kilometres, lay to the north of the village of Cu Chi.

The tunnels concealed living areas, storage depots, ordnance factories, hospitals, headquarters – a range of facilities than enabled people to live, and wage war from, underground for years at a time. When United States and Australian troops began sweeps into the area they had no idea of the tunnels' existence. Known as Operation Crimp and involving some 8,000 troops from the United States 1st Infantry Division, the 173rd Airborne Brigade and troops of the 1st Battalion, Royal Australian Regiment (1RAR), the attempt to defeat the Viet Cong in the Cu Chi district was, to that date, the largest American operation in Vietnam.

The Viet Cong were ready, having been bombed, shelled and seen reconnaissance aircraft overhead they knew that such preparations were followed by an offensive. The tunnels' defenders were heavily outnumbered, many of them were teenagers, some even younger, but in the kind of fighting for which they had been trained none of these factors were disadvantageous – space underground was limited and one or two men, familiar with the tunnels' layout could hold up a force and inflict casualties out of all proportion to their numbers.

The Australians and Americans had difficulty finding any enemy, but Viet Cong snipers caused a steadily rising number of casualties. As they moved through the Cu Chi district, United Stated and Australian troops encountered mines, foxholes, trenches and caves, but of Viet Cong there were almost no sightings. There was little fighting of the type expected in a major offensive and even when it became apparent that the enemy were present in tunnels beneath their feet, the difficulty in finding entrances made pursuing the Viet Cong difficult.

For the Australians, who had been dropped as a blocking force on Crimp's northern perimeter, the operation was a frustrating experience. By the third day their area of responsibility had been covered but no Viet Cong had been killed, or even seen. Only one conclusion could be reached, that the enemy were underground and as the Australians occupied the area they began to find the tunnels.

Over the next four days the Australians, along with the Americans, uncovered nearly two kilometres of communication tunnels, bunkers and underground chambers. During their introduction to tunnel warfare Australian troops found caches of ammunition, food and numerous booby traps. While they were developing systems for exploring the tunnels during Operation Crimp, the Australians had yet to devise methods of engaging in underground combat. By the time the operation ended on 14 January, the number of Australian dead in Vietnam had doubled from eight to sixteen. Behind them the Australians and Americans left empty and burnt villages. Their populations, considered too close to the Viet Cong, had been relocated.

Operation Crimp showed that the Viet Cong were a determined and well-organised enemy who had the ability to fight on their own terms, even against a major operation. The existence and the extent of the tunnel systems surprised the Americans and Australians. One year after Operation Crimp the Americans launched another offensive in the Cu Chi district and even after this second series of attacks, the tunnels survived. They were used as a base from which the Viet Cong launched attacks on Saigon during the 1968 Tet offensive. After the grievous casualties sustained by the Viet Cong in Tet, the war against America and its allies was carried more and more by the North Vietnamese Army and the role of the tunnels diminished. They had been crucial to the Viet Cong's prosecution of the war but in 1969 carpet bombing by United States aircraft rendered the tunnels uninhabitable.

Such was the rate of attrition among those who fought in the tunnels that of the 300 Viet Cong engaged in their defence when Operation Crimp began, only four survived the war. By Vietnamese estimates, some 12,000 Viet Cong and civilians lost their lives in Cu Chi during the war. The province has become a well-visited tourist destination because of the remnants of the wartime tunnels.


Last updated: 8 January 2019

Cite this page

DVA (Department of Veterans' Affairs) (2019), Viet Cong tunnels, DVA Anzac Portal, accessed 4 December 2020, http://anzacportal.dva.gov.au/wars-and-missions/vietnam-war-1962-1975/events/combat/viet-cong-tunnels
Was this page helpful?