The Xieng Khouang Plateau is located at the northern end of the Annamese Cordillera, the principal mountain range of Indochina. Initial research of the Plain of Jars in the early 1930s claimed that the stone jars are associated with prehistoric burial practices. Excavation by Lao and Japanese archaeologists in the intervening years has supported this interpretation with the discovery of human remains, burial goods and ceramics around the stone jars. The Plain of Jars is dated to the Iron Age (500 BCE to 500 CE) and is one of the most fascinating and important sites for studying Southeast Asian prehistory. The Plain of Jars has the potential to shed light on the relationship between increasingly complex societies and megalithic structures and provide insight into social organisation of Iron Age Southeast Asia’s communities. To visit the jar sites one would typically stay in Phonsavan.
More than 90 sites are known within the province of Xieng Khouang. Each site ranges from 1 up to 400 stone jars. The jars vary in height and diameter between 1 and 3 metres and are all without exception hewn out of rock. The stone jars are undecorated with the exception of a single jar at Site 1. This jar has a human bas-relief carved on the exterior. Parallels between this ‘frogman’ at Site 1 and the rock painting at Huashan in Guangxi, China have been drawn. The paintings, which depict large full-frontal humans with arms raised and knees bent, are dated to 500 BC - 200 AD.
From the fact that most of the jars have lip rims, it is presumed that all stone jars supported lids, although few stone lids have been recorded; this may suggest that the bulk of lids were fashioned from perishable materials. Stone lids with animal representations have been noticed at few sites such as Ban Phakeo (Site 52). The bas-relief animals are thought to be monkeys, tigers and frogs. No in situ lid has ever been found.
Not to be confused with stone lids are the stone discs. The stone discs have at least one flat side and are grave markers which were placed on the surface to cover or mark a burial pit. These gravemarkers appear more infrequently than stone jars, but are found in close proximity. Similar are stone gravemarkers; these stones are unworked, but have been placed intentionally to mark a grave. To the north of Xieng Khouang an extensive network of intentionally placed largely unworked stones marking elaborate burial pits and chambers are known as ‘standing stones of Huaphan’. Following the investigations by Colani, these were dated to the Bronze Age. Material associated with the stone grave markers in Xieng Khouang however, is similar to the stone jars artefacts.
The jars lie in clusters on the lower footslopes and mountain ridges of the hills surrounding the central plateau and upland valleys. Several quarry sites have been recorded usually close to the jar sites. Five rock types are known:sandstone, granite, conglomerate, limestone and breccia.
The majority of the jars are sandstone and have been manufactured with a degree of knowledge of what materials and techniques were suitable. It is assumed that Plain of Jars' people used iron chisels to manufacture the jars although no conclusive evidence for this exists. Regional differences in jar shape have been noted. While these differences in most cases can be attributed to choice and manipulation of rock source, form differences, such as small apertures and apertures on both ends (double holed jars) which would affect the use of the jar have been recorded in one district only.