Which cave site in Laos served as Pathet Lao headquarters during the Laotian Civil War?

The cave site in Laos that served as a Pathet Lao headquarters and wartime base was the Viengxay Caves.

Viengxay is an extensive cave network in Houaphanh Province in northeastern Laos. During the Second Indochina War, the Pathet Lao used the caves as a political, military, and civilian center while American bombing made surface life dangerous.

The settlement functioned like an underground town rather than a simple hiding place. It included offices, a hospital, a school, shops, bakeries, and a theatre, and as many as 23,000 people lived in the surrounding cave system. The caves also benefited from their proximity to the North Vietnamese border, which supported logistics and political connections.

The name is sometimes confused with other Laotian cave attractions, such as Kong Lor Cave or the Pak Ou Caves. Those sites are notable for geology or religious images, whereas Viengxay is specifically associated with the Pathet Lao’s revolutionary administration and wartime refuge.