republic · Mainland Southeast Asia

Khmer Republic

1970 CE – 1975 CE · capital Phnom Penh

The US-backed Cambodian republic of Lon Nol, which deposed Sihanouk in 1970 and fell to the Khmer Rouge in April 1975.

Origins

On 18 March 1970 Cambodia's national assembly, led by Prime Minister Lon Nol and Prince Sisowath Sirik Matak, voted to remove Norodom Sihanouk as head of state while he was abroad. The monarchy was abolished and the Khmer Republic proclaimed on 9 October 1970.

Rule and society

Lon Nol, who became president in 1972, sought to expel North Vietnamese forces from Cambodia and received US military aid. The republic was weakened by corruption, an inexperienced army and Lon Nol's ill health. US bombing of the countryside intensified, and the Khmer Rouge, now allied with the exiled Sihanouk, gained recruits. Refugees swelled Phnom Penh to over two million.

Decline and legacy

Khmer Rouge forces besieged Phnom Penh in early 1975. Lon Nol fled on 1 April, the US evacuated its embassy, and on 17 April 1975 the city fell. The Khmer Rouge emptied the capital and established Democratic Kampuchea.

Lineage

Kingdom of Cambodia (1953-1970) 1953 CE – 1970 CEKhmer RepublicDemocratic Kampuchea 1975 CE – 1979 CE

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Cite this page
APA
The Epoch Institute. (2026). Khmer Republic. In The Epoch Institute States Register. https://the-epoch-institute.org/state/khmer-republic
MLA
“Khmer Republic.” The Epoch Institute States Register, The Epoch Institute, 2026, https://the-epoch-institute.org/state/khmer-republic. Accessed .
Chicago
The Epoch Institute. “Khmer Republic.” The Epoch Institute States Register. 2026. https://the-epoch-institute.org/state/khmer-republic.
Harvard
The Epoch Institute (2026) ‘Khmer Republic’, The Epoch Institute States Register. Available at: https://the-epoch-institute.org/state/khmer-republic (Accessed: ).

Last reviewed October 2026Random state ↻