Between 4500 and 3500 years ago, partially intrusive Neolithic populations in the riverine basins of mainland Southeast Asia began to form mounded settlements and to develop economies based on rice cultivation, fishing, hunting, and the domestication of animals, especially pigs and dogs. A number of these sites have been excavated in recent years and they are often large mounds that can attain several meters in depth, comprising successive layers of alluvial soil brought in periodically to serve as living floors. The site of An Son is of this type and lies in a small valley immediately north of the Mekong Delta in southern Vietnam. Excavated on five occasions since 1978, and most recently in 2009, it was occupied from the late third into the late second millennium b.c . An Son has produced evidence that attests the domestication of pigs and dogs in all layers apart (perhaps) from the most basal one, which was not investigated in 2009, together with the growing of rice of the subspecies Oryza sativa japonica , of Chinese Neolithic origin. The oldest pottery has simple incised and punctate zoned decoration with parallels in central Thailand, especially in the basal phases at Nong Nor and Khok Phanom Di. From its middle and later occupation phases (1800–1200 b.c .), An Son has produced a number of supine extended burials with finely decorated pottery grave goods that carry some unique forms, especially vessels with wavy or serrated rims. The An Son burials represent a Neolithic population that expressed a mixture of both indigenous Hoabinhian and more northerly (probably Neolithic southern Chinese) cranial and dental phenotypes, perhaps representing a likely ancestral population for some of the modern Austroasiatic-speaking populations of mainland Southeast Asia.

An Son in southern Vietnam is one of a series of Neolithic (food producing) settlement/cemetery sites in Southeast Asia that appear, archaeologically, shortly before and after 2000 cal. BC. Excavations in 2009 produced a small but important assemblage of vertebrate remains that permit relative comparisons with other zooarchaeological assemblages of similar date in Thailand and northern Vietnam. At An Son, domestic dogs are present from the earliest known phases of occupation with butchery evidence and a high proportion of canid remains, suggesting they were possibly used as a food resource. Suid bones were recovered from the earliest phases of the site excavated, and pig husbandry can be identified from at least 1800 to 1600 cal. BC. There is also evidence for the use of a range of other resources including fishing, hunting and the capturing of turtles.

Research on prehistoric mainland Southeast Asia is dominated by mortuary contexts, leaving processes such as the transition to sedentism relatively understudied. Recent excavations in southern Vietnam, however, have recovered new evidence for settlement. The authors report on investigations at the neolithic site of Loc Giang (3980–3270 cal BP) in southern Vietnam, where excavation revealed a vertical sequence of more than 30 surfaces. Microarchaeological analyses indicate that these features are carefully prepared lime mortar floors; the lime was probably produced from burnt shell. The floors date to between 3510 and 3150 cal BP, providing the earliest-known evidence for the use of lime mortar, and for durable settlement construction, in this region.

In the tropics, outdoor areas are important arenas of social life and the scene of economic and daily activities. Yet, outdoor areas are not often detected due to destructive post-depositional processes and low archaeological visibility. Here we use microarchaeology to establish the settlement history and outdoor use of space at Lo Gach in Long An Province, southern Vietnam. The radiocarbon chronology identifies two phases of occupation: an initial presence at 3300-3000 cal. BP; and, later activity at 2750-2400 cal. BP. Microarchaeological analysis of the stratigraphy reveal complex sequences of organic waste severely transformed by chemical diagenesis. The results indicate that the excavated area at Lo Gach was an outdoor 'backyard' containing external surfaces utilised for a range of activities including rice processing, disposal of combustion residues, in situ burning, and recurrent foot traffic. Intensified rice agriculture and the systematic management of organic waste were the main structuring rhythms of social life that were performed at the Lo Gach settlement.

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