
The Cambodia–Vietnam border is the international border between the territory of
Cambodia
Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...
and
Vietnam
Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...
. The border is 1,158 km (720 mi) in length and runs from the
tripoint
A triple border, tripoint, trijunction, triple point, or tri-border area is a geography, geographical point at which the boundaries of three countries or Administrative division, subnational entities meet. There are 175 international tripoints ...
with
Laos
Laos, officially the Lao People's Democratic Republic (LPDR), is the only landlocked country in Southeast Asia. It is bordered by Myanmar and China to the northwest, Vietnam to the east, Cambodia to the southeast, and Thailand to the west and ...
in the north to
Gulf of Thailand
The Gulf of Thailand (), historically known as the Gulf of Siam (), is a shallow inlet adjacent to the southwestern South China Sea, bounded between the southwestern shores of the Indochinese Peninsula and the northern half of the Malay Peninsula. ...
in the south.
Description
The border starts in the north at the tripoint with Laos and then proceeds overland to the south, occasionally utilising rivers such as the
Tonlé San.
It then turns in a broad arc to the south-west, except for the Cambodian protrusion known as the
Parrot's Beak, running mostly overland but also at times using rivers such as the
Vàm Cỏ Đông and the
Saigon
Ho Chi Minh City (HCMC) ('','' TP.HCM; ), commonly known as Saigon (; ), is the most populous city in Vietnam with a population of around 14 million in 2025.
The city's geography is defined by rivers and canals, of which the largest is Saigo ...
. After cutting across the
Mekong delta
The Mekong Delta ( or simply ), also known as the Western Region () or South-western region (), is the list of regions of Vietnam, region in southwestern Vietnam where the Mekong, Mekong River River delta, approaches and empties into the sea th ...
it continues southwestwards, terminating at the Gulf of Thailand just west of
Hà Tiên
Hà Tiên is a Provincial city (Vietnam), provincial city in Kiên Giang Province, Mekong Delta in Vietnam. Its area is and the population as of 2019 is 81,576. The city borders Cambodia to the west. Hà Tiên is a tourist site of the region th ...
. The maritime boundary forms a loop, so
Phú Quốc island belongs to Vietnam despite it being closer to the Cambodia shore.
History
Vietnamese people gradually
migrated from northern Vietnam southwards during the 10th–18th centuries, eventually bringing them into contact with the Khmer kingdom.
Relations were often tense, with Vietnam frequently invading Cambodian lands; in 1857 a joint Siamese-Vietnamese protectorate was established over Cambodia.
From the 1860s
France
France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...
began establishing a presence in the region, initially in modern
Cambodia
Cambodia, officially the Kingdom of Cambodia, is a country in Southeast Asia on the Mainland Southeast Asia, Indochinese Peninsula. It is bordered by Thailand to the northwest, Laos to the north, and Vietnam to the east, and has a coastline ...
and
Vietnam
Vietnam, officially the Socialist Republic of Vietnam (SRV), is a country at the eastern edge of mainland Southeast Asia, with an area of about and a population of over 100 million, making it the world's List of countries and depende ...
, and the colony of
French Indochina
French Indochina (previously spelled as French Indo-China), officially known as the Indochinese Union and after 1941 as the Indochinese Federation, was a group of French dependent territories in Southeast Asia from 1887 to 1954. It was initial ...
was created in 1887, also including Laos.
A partial boundary between Cambodia and
Cochinchina
Cochinchina or Cochin-China (, ; ; ; ; ) is a historical exonym and endonym, exonym for part of Vietnam, depending on the contexts, usually for Southern Vietnam. Sometimes it referred to the whole of Vietnam, but it was commonly used to refer t ...
(southern Vietnam) in its southernmost section by the Gulf coast was drawn by the French in 1868–69 and then ratified in 1870.
This boundary was then modified slightly in 1873.
In 1904
Đắk Lắk was transferred from Laos to
Annam (central Vietnam) and
Stung Treng province transferred from Laos to Cambodia, with the rest of the Cambodia–Vietnam boundary as far north as the
Srepok River
The Srepok River (, ; Yagrai: Eă Srêpôkô; ) is a major tributary of the Mekong River.
Geography
Srepok River runs from Đắk Lắk Province in the Central Highlands of Vietnam through the Ratanakiri and Stung Treng provinces in Cambodi ...
then being delimited.
Various small adjustments were made to the alignment after this in the years 1914, 1932, 1933, 1935 and 1936.
In 1939
Jules Brévié,
Governor-General of French Indochina, divided the islands in the Gulf of Thailand on a purely administrative basis with the so-called 'Brévié line', however a scheduled allocation of the islands between Cambodia and Vietnam never took place.
In 1942 another small adjustment to the frontier was made in the vicinity of the Bassac River.
In 1954 both Cambodia and Vietnam gained full independence, however the latter was split into a Communist
North
North is one of the four compass points or cardinal directions. It is the opposite of south and is perpendicular to east and west. ''North'' is a noun, adjective, or adverb indicating Direction (geometry), direction or geography.
Etymology
T ...
and a capitalist
South
South is one of the cardinal directions or compass points. The direction is the opposite of north and is perpendicular to both west and east.
Etymology
The word ''south'' comes from Old English ''sūþ'', from earlier Proto-Germanic ''*sunþa ...
, with Cambodia bordering South Vietnam only.
The border remained undemarcated and numerous areas, as well as the Gulf islands, remained in dispute.
Furthermore, Khmer nationalists laid claim to much of the Mekong delta area of southern Vietnam (called ''Kampuchea Krom''), based on the fact that historically these were Khmer lands.
During the
Vietnam War
The Vietnam War (1 November 1955 – 30 April 1975) was an armed conflict in Vietnam, Laos, and Cambodia fought between North Vietnam (Democratic Republic of Vietnam) and South Vietnam (Republic of Vietnam) and their allies. North Vietnam w ...
the border was crossed by
Viet Cong
The Viet Cong (VC) was an epithet and umbrella term to refer to the communist-driven armed movement and united front organization in South Vietnam. It was formally organized as and led by the National Liberation Front of South Vietnam, and ...
supply lines, most notably the southern stretch of the
Ho Chi Minh Trail
The Ho Chi Minh Trail (), also called Annamite Range Trail () was a Military logistics, logistical network of roads and trails that ran from North Vietnam to South Vietnam through the kingdoms of Kingdom of Laos, Laos and Cambodia (1953–1970), ...
by the
Communist Party of Vietnam
The Communist Party of Vietnam (CPV) is the founding and sole legal party of the Socialist Republic of Vietnam. Founded in 1930 by Hồ Chí Minh, the CPV became the ruling party of North Vietnam in 1954 and then all of Vietnam after the col ...
(CPV), causing it to be heavily bombed by American forces.
In return for tolerating the Viet Cong presence along the border, Cambodia attempted to extract territorial concessions, though with little success.
On 17 April 1975, the totalitarian
Khmer Rouge
The Khmer Rouge is the name that was popularly given to members of the Communist Party of Kampuchea (CPK), and by extension to Democratic Kampuchea, which ruled Cambodia between 1975 and 1979. The name was coined in the 1960s by Norodom Sihano ...
regime led by the
Communist Party of Kampuchea (CPK) took over Cambodia including the capital
Phnom Penh
Phnom Penh is the Capital city, capital and List of cities and towns in Cambodia, most populous city of Cambodia. It has been the national capital since 1865 and has grown to become the nation's primate city and its political, economic, industr ...
and made gaining some or all of
Kampuchea Krom a priority as the
Cambodian Civil War
The Cambodian Civil War (, Romanization of Khmer#UNGEGN, UNGEGN: ) was a civil war in Cambodia fought between the Communist Party of Kampuchea (known as the Khmer Rouge, supported by North Vietnam and China) against the government of the Ki ...
came to an end.
A brief Khmer invasion occurring the day after
Saigon
Ho Chi Minh City (HCMC) ('','' TP.HCM; ), commonly known as Saigon (; ), is the most populous city in Vietnam with a population of around 14 million in 2025.
The city's geography is defined by rivers and canals, of which the largest is Saigo ...
fell to North Vietnam was repulsed on 30 April 1975 and has renamed
Ho Chi Minh City
Ho Chi Minh City (HCMC) ('','' TP.HCM; ), commonly known as Saigon (; ), is the most populous city in Vietnam with a population of around 14 million in 2025.
The city's geography is defined by rivers and canals, of which the largest is Saigo ...
, and border discussions then took place from 1976 to 1977. On 5 January 1976, Cambodia was renamed to
Democratic Kampuchea under the
Marxist-Leninist leaders of
Pol Pot
Pol Pot (born Saloth Sâr; 19 May 1925 – 15 April 1998) was a Cambodian politician, revolutionary, and dictator who ruled the communist state of Democratic Kampuchea from 1976 until Cambodian–Vietnamese War, his overthrow in 1979. During ...
and
Khieu Samphan
Khieu Samphan (; born 28 July 1931) is a Cambodian former communist politician and economist who was the chairman of the state presidium of Democratic Kampuchea (Cambodia) from 1976 until 1979. As such, he served as Cambodia's head of state a ...
. Vietnam was
reunified on 2 July 1976.
With relations deteriorating numerous skirmishes occurred along the border, with Vietnam eventually
invading Cambodia in 1978 and ousting the Khmer Rouge by the
Vietnamese Army on 7 January 1979.
Discussions on the border thereafter reconvened in 1983, with both sides in 1985 pledging to recognise the border as it was at independence.
Discussions continued into the early 1990s.
A treaty was signed in 2005, followed by on-the-ground demarcation, which was completed in 2012.
Border crossings

There are several border crossings:
* Bavet (
Bavet
Bavet (, ) is the largest city in Svay Rieng Province, Cambodia. An international border crossing between Cambodia and Vietnam, its counterpart across the border is Mộc Bài of Tây Ninh Province, Vietnam.
Bavet is one of the "special econo ...
,
Svay Rieng, Cambodia) –
Mộc Bài
Mộc Bài is an international border gate between Vietnam and Cambodia located in Tây Ninh Province, Vietnam. Its counterpart across the border is the Bavet border gate, Svay Rieng Province, Cambodia. As it is located on the main highway between ...
(
Bến Cầu,
Tây Ninh, Vietnam)
* Prey Voa (
Kampong Rou,
Svay Rieng, Cambodia) –
Bình Hiệp (
Kiến Tường,
Long An, Vietnam)
* Trapeang Sre (
Snuol,
Kratié, Cambodia) –
Hua Lư (
Lộc Ninh,
Bình Phước, Vietnam)
* Trapeang Phlong (
Trapeang Phlong,
Tboung Khmum, Cambodia) –
Xa Mát (
Tân Biên,
Tây Ninh, Vietnam)
* Muern Chey (
Kamchay Mear,
Prey Veng, Cambodia) –
Tân Nam (
Tân Biên,
Tây Ninh, Vietnam)
* Kaoh Roka (
Peam Chor,
Prey Veng, Cambodia) –
Thường Phước (
Hồng Ngự,
Đồng Tháp, Vietnam)
* Banteay Chakrei (
Preah Sdach,
Prey Veng, Cambodia) –
Dinh Bà (
Tân Hồng,
Đồng Tháp, Vietnam)
* Kaam Samnor (
Leuk Daek,
Kandal, Cambodia) –
Vĩnh Xương (
Tân Châu,
An Giang, Vietnam)
* Phnom Den (
Kiri Vong,
Takéo, Cambodia) –
Tịnh Biên
Tịnh Biên is a district-level town (''thị xã'') of An Giang province in the Mekong Delta region of Vietnam.
As of 2022, the town had a population of 143,098. The town seat lies at Tịnh Biên ward.
The Tịnh Biên frontier market is l ...
(
Tịnh Biên
Tịnh Biên is a district-level town (''thị xã'') of An Giang province in the Mekong Delta region of Vietnam.
As of 2022, the town had a population of 143,098. The town seat lies at Tịnh Biên ward.
The Tịnh Biên frontier market is l ...
,
An Giang, Vietnam)
* Prek Chak (
Kampong Trach,
Kampot, Cambodia) – Hà Tiên (
Hà Tiên
Hà Tiên is a Provincial city (Vietnam), provincial city in Kiên Giang Province, Mekong Delta in Vietnam. Its area is and the population as of 2019 is 81,576. The city borders Cambodia to the west. Hà Tiên is a tourist site of the region th ...
,
Kiên Giang, Vietnam)
* Oyadav (
Ou Ya Dav,
Ratanakiri, Cambodia) – Lệ Thanh (
Đức Cơ,
Gia Lai, Vietnam)
See also
*
Cambodia–Vietnam relations
*
Cambodia (Kampuchea)
*
Communist Party of Kampuchea (CPK)
*
Kampuchea Revolutionary Army (RAK)
*
Kampuchean People's Representative Assembly
The Kampuchean People's Representative Assembly (, ) was the official name of the unicameral legislature of Cambodia during the Democratic Kampuchea period. It was established as the official legislature of Kampuchea on 5 January 1976, consistin ...
*
Patriotic and Democratic Front of the Great National Union of Kampuchea (PDFGNUK)
References
{{DEFAULTSORT:Cambodia-Vietnam border
Cambodia-Vietnam border
border
Borders are generally defined as geography, geographical boundaries, imposed either by features such as oceans and terrain, or by polity, political entities such as governments, sovereign states, federated states, and other administrative divisio ...
Borders of Cambodia
Borders of Vietnam
International borders