In the aftermath of withdrawal from Vietnam the US military tended to turn its back on insurgency/counterinsurgency. Events since 2001 have, however, thrust this type of warfare back onto its institutional agendas. How long the trend will continue is unclear but so far the early 21st Century has been another "counterinsurgency era" in American military history. This may, therefore, be an appropriate moment to take a fresh look at the Buon Enao experiment: one of the most sophisticated counterinsurgency efforts that Americans have ever conceived and mounted. A small village in South Vietnam's Central Highlands, Buon Enao became the starting point for a defence complex that embraced much of Darlac, amongst the country's largest provinces, checking the Communist surge there and, to a considerable degree, rolling it back. The Buon Enao experiment, moreover, initiated the Civilian Irregular Defense Group (CIDG) programme: the biggest programme involving US Army Special Forces personnel during the Second Indochina War. It would be inaccurate to suggest that the Buon Enao experiment has been forgotten. It is, at least in broad outline, familiar to those with a substantial knowledge of the history of American counterinsurgency and that of US Special Forces. Yet, though recognized as important and referred to in a plethora of publications, it lacks the full scholarly treatment it deserves and most of the brief published accounts available contain inaccuracies that require correction. The present article is intended as a modest step towards a thorough academic appraisal: a reasonably detailed, accurate record of events accompanied by some tentative analysis of Buon Enao in relation to the further development of the CIDG program in Vietnam and subsequent US Army approaches to counterinsurgency.