China’s complex natural conditions have produced an unevenly distributed population. Population density varies strikingly, with the greatest contrast occurring between the eastern half of China and the lands of the west and the northwest. Exceptionally high population densities occur in the Yangtze delta, the Pearl River Delta, and on the Chengdu Plain of the western Sichuan Basin. Most of the high-density areas are coterminous with the alluvial plains on which intensive agriculture is centered.

In contrast, the isolated, extensive western and frontier regions, which are much larger than any European country, are sparsely populated. Extensive uninhabited areas include the extremely high northern part of Tibet, the sandy wastes of the central Tarim and eastern Junggar basins in Xinjiang, and the barren desert and mountains east of Lop Nur.

In the 1950s the government became increasingly aware of the importance of the frontier regions and initiated a drive for former members of the military and young intellectuals to settle there. New railways and highways were constructed to traverse the wasteland, and this has spurred population growth and the development of a number of small mining and industrial towns.

Internal migration

Great population movements have been a recurring theme throughout Chinese history. Typically, some disastrous event such as famine or political upheaval would depopulate an area already intensively cultivated, after which people in adjacent crowded regions would move in to occupy the deserted land. A farmer rebellion in Sichuan in the 1640s caused great loss of life there, and people from neighboring Hubei and Shaanxi then entered Sichuan to fill the vacuum; this migration pattern continued until the 19th century. Three centuries later the Taiping Rebellion caused another large-scale disruption of population. Many people in the lower Yangtze valley were massacred by the opposing armies, and the survivors suffered from starvation. After the rebellion was defeated, people from Hubei, Hunan, and Henan moved into the depopulated areas of Jiangsu, Anhui, and Zhejiang, where farmland was lying abandoned and uncultivated. Similar examples include the Nian Rebellion in the Huai River region in the 1850s and ’60s, the Muslim rebellions in Shaanxi and Gansu in the 1860s and ’70s, and the great Shaanxi and Shanxi famine of 1877–78.

The most significant internal population movement in modern Chinese history was that of the Han to Manchuria (now known as the Northeast). Even before the Qing (Manchu) dynasty was established in 1644, Manchu soldiers had launched raids into North China and captured Han laborers, who were then obliged to settle in Manchuria. An imperial decree in 1668 closed the area to further Han migration, but this ban was never effectively enforced. By 1850, Han colonizing settlers had become dominant in Manchuria. The ban was later partially lifted, partly because the Manchu rulers were harassed by disturbances in China proper and partly because the Russian Empire continually tried to invade sparsely populated and thus weakly defended Manchuria. The ban was finally removed altogether in 1878, but settlement was encouraged only after 1900.

The influx of people into Manchuria was especially pronounced after 1923, and incoming farmers rapidly brought a vast area of virgin grassland under cultivation. About two-thirds of the immigrants entered Manchuria by sea, and one-third came overland. Because the region’s winter weather was so severe, migration in the early stage was highly seasonal, usually starting in February and continuing through the spring. After the autumn harvest a large proportion of the farmers returned south. As Manchuria developed into the principal industrial region of China, however, large urban centers arose there, and the nature of the migration changed. No longer was the movement primarily one of agricultural resettlement, and instead it became essentially a rural-to-urban movement of interregional magnitude.

After 1949 the new government’s efforts to foster planned migration into interior and border regions produced noticeable results. Although the total number of people involved in such migrations is not known, it has been estimated that by 1980 between one-fourth and one-third of the population of such regions and provinces as Inner Mongolia, Xinjiang, Heilongjiang, and Qinghai consisted of recent migrants, and migration had raised the proportion of Han in Xinjiang to about two-fifths of the total. Efforts to control the growth of large cities led to the resettlement in the countryside of some 20 million urbanites after the failure of the Great Leap Forward and of nearly the same number of urban-educated youths in the decade after 1968. However, most of these “rusticated youths” subsequently returned to the cities.

The economic reforms begun in the late 1970s have unleashed a tidal wave of both rural-to-urban and west-to-east migration, reversing trends of the previous three decades. This has further exacerbated the country’s uneven population distribution, bringing enormous influxes to the urban areas of the eastern provinces and further depleting the population in the western regions. However, tens of millions of rural people who go to the cities to find jobs also return home for periods of time during the year. These individuals have tended to group themselves according to their native area for mutual benefit, much as ethnic groups have done in other major world cities. However, the unregulated influx of so many migrants and the instability of their lives and work have put considerable strain on the host cities, notably the environment and public security.