Over the decades, some movement of the rural population in Cambodia-- either to urban areas in quest of employment or to other villages in search of more favorable agricultural sites--has been customary. Many highland tribal groups practice slash-and-burn agriculture that requires movement to a new area once the soil is exhausted in a given location. Warfare in the early 1970s drove large numbers of rural people to the cities in search of safety. The population of Phnom Penh, for example, increased from 393,995 in 1962 to about 1.2 million in 1971, but had decreased to about 500,000 by 1985. With their takeover in April 1975, the Khmer Rouge forced most of the population out of Phnom Penh into the countryside, where large numbers either died because of hardship or were executed. Many such population movements were forced upon the populace under the Khmer Rouge regime. Many Cambodians who had left the country to study abroad became de facto emigrants when the communists took over. Thousands more fled into neighboring Thailand and Vietnam in 1975 and at the time of the Vietnamese invasion in late 1978. Cham, Vietnamese, and Chinese communities alike were persecuted, and their members were killed, under the Khmer Rouge. Forced repatriation in 1970 and deaths during the Khmer Rouge era reduced the Vietnamese population in Cambodia from between 250,000 and 300,000 in 1969 to a reported 56,000 in 1984. Postwar emigration of Vietnamese civilians to Cambodia remained a subject of controversy. Some social scientists believed that the number of Vietnamese in Cambodia in 1988 had reached at least the prewar level, and, indeed, many Khmer feared that even more Vietnamese immigrants would inundate their population.

During the Khmer Rouge era, about 50,000 Cambodians fled to Thailand, and an estimated 150,000 fled to Vietnam. As soon as the Khmer Rouge regime began to crumble under the onslaught of the Vietnamese in late 1978, a massive exodus of Cambodians began. About 630,000--braving hostile fire, minefields, bandits, and border guards--left the country between 1979 and 1981. In subsequent years, about 208,000 resettled in other countries these included 136,000 in the United States, 32,000 in France, and 13,000 each in Australia and in Canada.

In late 1987, about 265,000 Cambodians--about 150,000 of them below the age of 15 remained in Thailand. The Khmer refugees were supported by the United Nations Border Relief Operation (which assumed the task from the United Nations High Commissioner for Refugees in the early 1980s) and private agencies at an annual cost of US$36 million in 1986. The refugees were grouped in nine camps on the Thailand side of that country's common border with Cambodia. Of the nine installations, the most prominent was Khao-I-Dang, located near Aranyaprathet, Prachin Buri Province, Thailand. It was controlled by the Thai military, and its inhabitants were the only ones to be regarded legally as refugees by the Thai government. In 1987 Khao-I-Dang had a population of about 21,000 to 25,000 (down from a peak of 130,000 at its founding in 1979), of whom about 1d5e 12,000 to 15,000 were eligible for resettlement.

The other eight camps were under the control of the three Khmer resistance factions (see Coalition Government of Democratic Kampuchea , ch. 4 Coalition Government Resistance Forces , ch. 5). These camps were considered reception centers rather than bona fide refugee facilities by the Thai government, and their inmates, unlike the residents of Khao-I-Dang, were considered displaced persons rather than refugees. Of these eight installations, five were controlled by the Khmer Rouge two, by the Khmer People's National Liberation Front (KPNLF--see Appendix B) and one, by the Sihanouk National Army (Armée Nationale Sihanoukiste--ANS--see Appendix B). Khmer insurgents freely visited the camps controlled by their own resistance factions and used them as rest and recuperation centers.

The Khmer Rouge camps sheltered between 50,000 and 60,000 inhabitants. Access to them was granted grudgingly, if at all, even to United Nations officials. Occasional visiting journalists reported in the 1980s that an atmosphere of repression and fear prevailed at these facilities. The largest Khmer Rouge installation, located on the southwestern part of the border between Cambodia and Thailand, was known as Site 8 and held about 30,000 persons. Smaller installations, inhabited by 20,000 or more people altogether, were reported at Na Trao and Huay Chan, in Sisaket Province, Thailand, and at the seldom-visited encampments of Borai and in Ta Luen, Trat Province, Thailand.

The KPNLF controlled two camps containing a total of about 160,000 persons. The principal installation was Site 2, with a population of between 145,000 and 150,000 and an environment noted for its rampant lawlessness. Site 2 was located in the vicinity of Ta Phraya, Prachin Buri Province, Thailand, and, at one time in the early 1980s, held the largest concentration Cambodians outside of Phnom Penh.

The lone camp controlled by the ANS was Site B, also known as "Green Hill," which was located about 50 kilometers north of Ta Phraya and had a population of between 40,000 and 50,000. Site B was considered by observers to be the most orderly and well-managed of the refugee camps it offered more living space, including room for personal gardens, than did the others.

Data as of December 1987