During the third millennium BC, intensive farming became widespread along the Yellow and Yangzi River regions, where we also see the highest population densities and the most developed complex societies in the archaeological record. In contrast, hunting-gathering communities, sometimes incorporating low-level food production, appear to have continuously dominated the landscapes in many other areas, such as the Northeast, Xinjiang, most areas in the Tibetan Plateau, and some parts of South China.

In the highly populated regions, some major social changes took place. Most of these societies were hierarchically organized, exchange of prestige goods was a common practice among elite individuals, and intergroup warfare intensified. Political control, ritual power, and material wealth were closely related and concentrated in small groups of elites. Regional centers were frequently built with walled enclosures, and some developed early forms of urbanism with political, religious, and economic functions. In ancient Chinese texts the polities in the Yellow River region have been referred to as “myriad (literally, ‘ten thousand’) states” prior to the first dynasty, the Xia.