After the Vietnamese invasion of Cambodia in January 1979, hundreds of thousands of Cambodian refugees fled to the border camps on the Cambodia-Thailand border. Some refugees lived inside the UNHCR camps like Khao I Dang, Sra Keo, and Site 2, while others were stuck inside camps under the control of the resistance forces like the KPNLF, Funcinpec and the Khmer Rouge. (http://www.websitesrcg.com/ border/border-camps.html).
Some refugees in the Khao I Dang camp were eligible for resettlement in the third countries, e.g. Australia, Canada, France and USA. It was estimated that some 206,000 Cambodian refugees were eventually resettled in the USA.
Following the signing of 1991 Paris Peace Agreement, and between 1992 and 1999, more than 350,000 of Cambodian refugees from various camps on the Cambodia-Thailand border were repatriated to Cambodia. The majority of those were resettled in the northwest of Cambodia like Battambang and Banteay Mean Chey provinces.

UN Photo/Pernaca SudhakaraHere are stories of their harrowing experiences.
(1) REFUGEE WARRIORS AT THE THAI-CAMBODIAN BORDER
(2) Krour Sar Thmei- A Story of Khmer orphans returning from Site 2 Refugee camp (Thailand) in 1992
(3) Dangerous Life on Thai-Cambodian border - late 1979
(4) Thai Army's atrocity at Mount Dangrek: Khmer Refugees' tragic stories
(5) Where Are They Now?
(6) Radio Current Affairs Documentary: Kosal Khiev
(7) Sovan Goldstraw nee Uon's migration memories
(8) Restaurateur share how he survives the Killing Fields