An important characteristic of historic and modern China is environmental and cultural diversity. It is likely that this diversity characterizes the prehistoric period as well. As a point of comparison, mainland China is roughly the same size as that of the United States, with similarly diverse environmental and climatic zones. Most scholars refer to the areas north of the Yangzi (Yangtze, or Changjiang) River as northern China. Millet agriculture is more common in the north, while rice is grown more extensively in the south.
Archaeologists have focused their research in three areas of north China: the northeast, the central Yellow River (Huang He) valley, and the lower Yellow River valley. Increasingly, more fieldwork is taking place at Neolithic sites in mountainous areas further west. Northeast China, formerly referred to as Manchuria by some, is environmentally diverse. There are deciduous forests, steppes, mixed conifer and hardwood forests, and boreal forests. In comparison to areas further south, the growing season is short, with harsh winters. Northeast China includes the modern provinces of Liaoning, eastern Inner Mongolia (Nei Menggu), Jilin, and Heilongjiang. The central and lower Yellow River valley areas have deciduous broadleaf forests, fertile loess soil (yellowish silt), and a temperate climate.
A distinctive topographic zone where intensive archaeological research has taken place is the North China Plain (including parts of eastern Shaanxi, southern Shanxi, southern Hebei, Henan, and western Shandong provinces). Many archaeologists refer to a distinct cultural area called the Central Plain, focusing on Henan, where the early Bronze Age states developed. They contrast the Central Plain area with the Haidai (eastern seaboard) area (including Shandong, northern Jiangsu, and northern Anhui). In recent years, however, stunning discoveries have been made in several areas of China, showing that diverse cultures contributed to the development of early Chinese civilization.
Research has been conducted primarily in three areas of south China: the central Yangzi River valley, the lower Yangzi River valley, and southernmost China (here, including Hong Kong and Taiwan). The Neolithic cultures of mountainous southwest China are not as well known at present. Judging from the major discoveries of Palaeolithic and Bronze Age sites there (see Asia, East: China, Paleolithic Cultures), the area will provide more information on life ways during the Neolithic period. The Yangzi River valley has both mixed deciduous broadleaved evergreen forests and subtropical broadleaved evergreen forests. There is more rainfall than in the north, and the climate is warmer. Other distinctive features include bamboo forests and large, freshwater lakes. The central Yangzi River valley includes the modern provinces of southern Hubei, northern Hunan, and northern Jiangxi. The lower Yangzi River valley includes the modern provinces of southern Anhui, southern Jiangsu, and northern Zhejiang. Southernmost China is characterized by subtropical broadleaved evergreen forests and striking limestone mountains. The climate ranges from subtropical to tropical, and crops can be grown all year. Taro is an important root crop that is not found further north. There is abundant rainfall, and typhoons are common in the summer months. In these areas of south China and the Yangzi River valley, fishing is particularly important. The Republic of Taiwan includes the island of Taiwan, as well as other small islands.
The largest ethnic group of mainland and insular China is referred to as the Han. Several ethnic minority groups have been known to reside in all areas since the early historic era. These historically known ethnic minority cultures are similar to those in neighboring countries to the north, west, and south. On the mainland, most ethnic minority peoples live in western areas. Many of these peoples have had nomadic lifestyles, moving seasonally with their herds. In several areas, ethnic minority peoples still speak their own languages, while written languages have been recorded for some. It is likely that diverse peoples, languages, and cultural traditions characterized the Neolithic period as well.