INTERNATIONAL BOUNDARIES OF INDOCHINA

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• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP84-00825R000100140001-0
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• Document Creation Date: December 15, 2016
• Document Release Date: March 22, 2002
• Sequence Number: 1
• Publication Date: March 1, 1965
• Content Type: IM

SECRET Approved For Release 2002/05/09 : CIA-RDP84-00825R000100144643-15 No. 259
INTELLIGENCE MEMORANDUM
CIA/RR GM 65-2
March 1965
INTERNATIONAL BOUNDARIES
OF INDOCHINA
CENTRAL INTELLIGENCE AGENCY
OFFICE OF RESEARCH AND REPORTS
WARNING
This material contains information affecting the National Defense of the United States within
the meaning of the espionage laws, Title 18, USC, Secs. 793 and 794, the transmission or
revelation of which in any manner to an unauthorized person is prohibited by law.
SECRET
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SECRET
Interior Boundaries
Vieftwa-Laos Broundorx
The Laos boundary with North Vietnam is in dispute. The entire Vietnam
- Laos boundary was delimited and surveyed by France before the dissolution
of French Indochina, but it has never been denarcated. The boundary is
1,336 miles long. For almost 1,150 miles it coincides with the primary
drainage divide of the mountains of northern Indochina and the Chafne Anna-
mitique and with minor divides within the mountain ranges. Rivers and
streams form the boundary for another 148 miles, and two straight-line seg-
ments (see Figure 5) totaling 38 miles complete the boundary. In the vicin-
ity of the upper course of the Se Kamane, the easternyost point on the Viet-
nam - Laos frontier, the exact location of the boundary is unknown for a
distance of approximately 32 miles, even though the entire boundary presum-
ably has been surveyed. US Government cartographic policy is to show this
segment of the boundary by means of an "indefinite" boundary symbol along the
drainage divide.
North Vietnamese maps published in 1964 differ markedly from US and
French Government maps in their delineation of five sectors of the Vietnam
- Laos boundary (see Map 51019).5 Two discrepancies are the result of North
Vietnamese reliance upon older, inaccurate French map sources. These two
Involve (1) the sector of the boundary extending northward from the trijunc-
tion of South Vietnam, Cambodia, and Laos to about 160N and (2) the sector
from about 20000' to 20035'N. A third discrepancy involves a triangular area
at about 20.40'N 103.45'E, for which no cartographic or other logical expla-
nation is apparent.
The remaining two areas of difference in boundary alignment appear to be
deliberate cartographic misrepresentations by North Vietnam, possibly as a
basis for claiming land that now belongs to Laos. One of these areas is bi-
sected by Route 7 where it crosses the North Vietnam - Laos frontier. The
North Vietnamese map shows the border 2 to 7 miles west of its position on
French and US Government maps.
The last of the five areas of boundary discrepancy is the most important.
This is the segment that is bisected by the 17th parallel; part of it forms
the western limits of the Demilitarized Zone (DMZ) and is currently in dis-
pute, as evidenced by North Vietnamese claims that "their" villages are being
bombed although the villages named are in Laos, west of the border. In 1954
and again in 1958 North Vietnamese forces had occupied and claimed approxi-
mately the some area of Laos. The segment in question was originally estab-
lished in October 1916, by decree of the Governor General of Indochina, to
serve as the border between areas that were then the provinces of Querns Tri
(Annam) and Savannakhet (Laos)... In 1937, after discovering Vietnamese
agents of the court of Hug collecting taxes in the area west of the frontier,
French authorities established an area of Vietnamese influence and ordered
the Vietnamese not to penetrate beyond this area (see Maps 51019 and 51020).
The area was roughly in the form of an isosceles triangle with the straight
segment of the boundary as the base line and the apex 23 kilometers (14.29
miles) west of the center of the base line. Although the line forming the
triangle was never formally decreed as part of the boundary, it is signifi-
cant that the villages that North Vietnam claims were being bombed as of late
1964 are generally within the limits of the northern half, of this triangle
and north of an imaginary extension of the Demarcation Line. The villages
of Ban Riac and Ban Trim were bombed by the Laotian Air puree in late 1964,
but the Hanoi regime did not mention them by name, possibly because they are
located south of the latitude of the Demarcation Line.
Cambodia?Soma ViehmumBoundMzz
Much of the boundary between Cambodia and South Vietnam is in dispute.
The land sector was delimited by various French administrative actions be-
ginning in the latter part of the 19th century. Although there is evidence
that the southern segment (Cochin China) was demarcated in the 1870's, most
of the markers apparently have been destroyed through either natural causes
or deliberate actions of South Vietnam or Cambodia. A water boundary, in
the sense of an agreed line dividing the various offshore islands, does not
exist; instead, Canbodia and South Vietnam claim various islands, and in
many instances their claire conflict.
Land Sector -- The land 'sector of the boundary between Cambodia and South
Vietnam extends from the South Vietnam - Laos - Cambodia trijunction south-
ward for about 600 miles to the Gulf of Siam. The northern portion, border-
ing the South Vietnam highlands, is generally aligned along drainage divides.
The southern portion, through the flat Mekong Delta, is more complex in align-
ment, as the various segments follow rivers, right or left banks of rivers
and canals, and straight lines. The difficulty of locating the boundary in
the Mekong Delta is compounded by the uniform appearance of the flat terrain,
particularly when seasonal floodwaters have submerged distinguishing landmarks
(see Figure 6).
In March 1964, Cambodia furnished the United States with annotated sheets
of the French Service Geographique map series at 1:100,000 that showed the
official Cambodian boundary claim. A comparison of this boundary alignment
with the alignment accepted by South Vietnam, which is shown on more recently
published French naps of the same series, reveals seven areas of difference
in Cambodian and South Vietnamese claims (see Map 51019). All of them are
minor and probably are only differences in cartographic representation.
In January 1965, however, Cambodia in a note to South Vietnam advanced
claims to several areas of South Vietnam that she had claimed historically
but that had been ceded to Vietnam through various French decrees. These in-
cluded: (1) part of the Cambodian province of Stung Treng, which was incor-
porated into Darlac Province of Armem in 1899, (2) four districts (cantons)
in the Inc Ninh area, which were annexed to Cochin China by decrees of 1893
and 1914, (3) certain areas in the vicinity of Tay Ninh, which were annexed
to Cochin China in 1869-70, (4) the enclave between the Vaico Oriental (Song
Van Co Dons) and the Vaico Occidental (Song Van Co Tay), which was given to
Cochin China in 1870, and (5) the communes of Koh Chauloh and Sakfy, neer HA
Tien, on the Gulf of Siam, which were given to Cochin China by a decree of
1914.
. The most detailed map coverage of the Vietnam - Laos'boundary and the Cam-
bodia.- South Vietnam boundary is provided by selected sheets of the Anny Map
Service Series' L701, L7011, and L7012 at 1:50,000. Publication of all sheets
relating to the boundaries south of the 17th parallel was scheduled for com-
pletion by 15 March 1965.
.. The decree stated that "the border starts at Peak 1221 and follows from
north to south 11567' until it meets bench mark 1020 M 82 of Doug Ta Poe."
(The centesimal system sometimes used for French mapping expresses coordi-
nates in grads rather than degrees, 400 grads being equal to 360 degrees;
longitude is based on Paris rather than Greenwich.) Actually the boundary
follows 115678.5', and this meridian was used on the map attached to the 1954
Geneva Armistice Agreement, which created the DMZ; the map was accepted by
all signers of the agreement, including Pham Van long, who signed for North
Vietnam and is now its premier.
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Speculation as to why Cambodia has seen fit to raise these claims at this
time ranges from the feeling that the claims nay be a sop to the Khmer Kram,
the ethnic Cambodians who live in South Vietnam, to the belief that Prince
Sihanouk sees them as an aggressive counter to South Vietnamese claim: to is-
lands in the Gulf of Siam. In his speech to the Cambodian Nationel Congress
on 28 December 1964 Sihanouk claimed that it had not been possible to sign
boundary agreements with the Hanoi regime and the Communist National Front
for the Liberation of South Vietnam (NFL) chiefly because the Communist nego-
tiators at Peiping had rejected Cambodian requests for special minority treat-
ment for the Khmer Kamm.
Water Sector -- Cambodia's island claims, portrayed on an annotated French
nautical chart, Des ties Balua a la Rivi? de Kbh Pau, transmitted to the United
States in 1964, conflict with South Vietnam's claims as indicated by the seaverd
extension of the international boundary on South Vietnamese-produced maps (see
Map 51019). South Vietnamese claims to Hon Phu Du, Hon Nuoc, and Hon Antay
probably are most disturbing to Cambodia, as these islands are strategically
close to the Cambodian mainland. Several of the islands claimed by Cambodia
have been occupied by South Vietnamese forces at various tines since 1960.
Cambodia claims offshore territorial waters within 5 nautical miles (5.75
statute miles).
Available evidence indicates that in the middle of the 19th century all
of the islands in question belonged to Canbodia. Some time after Cochin
China became a colony of France in mid-1862, he du Milieu, he h l'Eau, tle
du Pic, Ile de Phu Spun, and some other islands in the Gulf of Siam came
under the administration of the Governor of Cochin China. Disagreement over
administration of the islands apparently continued into the early 20th century.
Finally, in January 1939 the Governor General of Indochina decreed that the
limits of insular administrative responsibility of Cambodia and Cochin China,
respectively, would be defined by a straight line extending seaward from the
mainland near Ha Tien at a bearing of 234 degrees, except in the vicinity of
tie de Phu Quoc where the line looped 3 kilometers (1.62 nautical miles)
north of the island in order to include this water-and-land area under Cochin
Chinese administration. All islands north of the line were to be adminis-
tered by Cambodia, and those to the south were to be administered by Cochin
China. The decree was intended to facilitate administration of the islands
and expressly disavowed any intention of attempting to divide them on the
basis of sovereignty.
Although the 1939 decision is now accepted as an administrative device,
it is noteworthy that as recently as 1957 some Cambodian Officials, including
the Navy Chief of Staff, accepted the Governor General's line as a de facto
boundary. This acceptance may have juridical significance in view of the
precedent net by the 1962 decision of the International Court of Justice (ICJ)
to award the Preah Vihear Temple boundary area to Canbodia on the ground that
Thailand as well as Cambodia had acknowledged past acceptance of the delimita-
tion of that boundary as shown on a specific map.
Lass ?Cambodia Boands,7
The Laos - Cambodia boundary was delimited by various French declarations
of protection and by internal administrative actions of the former French
Indochinese Government rather tdan by the usual international agreements.
No demarcation has been effected, but the boundary segment vest of the Mekong
River follows the Tonle Repou and technically may be considered demarcated.
There appears to be no dispute between Laos and Cambodia concerning this
boundary. Representation of the boundary on North Vietnamese-produced maps,
however, differs from that on current official US and French maps, presumably
because the Vietnamese maps were compiled from older, inaccurate French maps.
The boundary extends westward about 336 miles from its junction with the
South Vietnam boundery'at?107037'E 14041'N to its junction with the Thai
boundary at Col de Fresh Chambot (pass) in the Cheine des Dangrek (mountains).
For most of its length the boundary follows drainage divides; elsewhere it is
aligned along major and minor streams.
The first definition of the boundary was contained in the 1893 treaty
between France and the Kingdom of Siam, by which France forced expanding Siam
to give up all teriltbry east of the Mekong River. As a result of this
treaty, the former Canbodian province of Stung Treng (part of which now com-
prises the Cambodian provinces of Stung Treng and Ratanakiri) became part of
French Laos. It retained this statue until December 1904, when it was divided
between Cambodia and Amu= (now South Vietnam) by French administrative decree.
In 1902 Siam ceded to France the territory on the right bank of the Mekong,
which had belonged to Cambodia in the 18th century, and this territory became
the southwestern part of Laos. It seems virtually certain that French author-
ities further defined the Laos - Cambodia boundary by administrative action
after 1904.
The prinary source for the delineation of the Laos - Cambodia boundary is
the Carte de l'Indochine 1:100.000 published by the French Service Geographique
So l'Indochine. An older map series, Carte Routiare de l'Indochine at 1:400,000,
published by the Institut Geographique National (Paris Y, portrays the boundary
inaccurately.
names Demarcation Line
The Vietnam Demarcation Line is not an international boundary. It is a
provisional line approximately 47 miles long that implements the partition
effected by the Agreement on Cessation of Hostilities signed at Geneva on
20 July 1954. This agreement brought an end to hostilities between the
French Union-Vietnamese forces and forces of the Viet Minh. The line follows
the course of the Song Ben Hai from its mouth to the village of Bo Ho Su and
then extends due west to the Vietnam - Laos boundary (see Map 51020).
A demilitarized zone that varies in width from somewhat less than 4 miles
to almost 6 miles extends north and south of the Demarcation Line. The bound-
aries of this zone are delimited by Ruling No. II, issued on 15 September 1954
in accordance with the July 1954 agreement. East of the village of Thuy Ha On
on the north and east of Thema the village on the south, the limits of the sone
have been marked by posts at intervals of 300 to 500 meters (975 to 1,625 feet).
West of these villages, markers were to have been erected at 1-kilometer (0.62-
mile) intervals, but there is no evidence that this work was accomplished.
A seaward extension of the Demarcation Line is provided for by Article 4
of the 1954 agreement, which provides that "The provisional military demar-
cation be between the two final regrouping zones is extended into the
territorial waters by a line perpendicular to the general line of the coast."
The governments of North Vietnam and South Vietnam differ, however, in their
interpretation of the extent of territorial waters. North Vietnam defines
the width of its territorial waters as 12 nautical miles, whereas South
Vietnam recognizes a 3-nautical mile limit.
The alignment of the Demarcation Line and the boundaries of the Da are
shown on the 1,25,000 maps attached to the official agreement.
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INTERNATIONAL BOUNDARIES
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SECRET
Exterior Boundaries
North Vietnam-Mina Boundstrz
The boundary between North Vietnam and Communist China was delimited by
treaties between France and China in 1887 and 1895. The 1887 treaty related
to the section between the Gulf of Tonkin and the Black River, whereas the
1895 treaty delimited the section west of the Black River. Demarcation
commissions narked the boundary shortly afterwarda, and it is not currently
in dispute. The treaties governing the boundary are accepted by the Republic
of China (Taiwan).
The boundary, 796.4 miles in length, for the most pert follows crests of
ridges and hills in rugged, remote areas that are sparsely populated by trib-
al people. Rivers and streams form the frontier for 218.4 miles, or about
27 percent of its total length. At least 285 pillars, approximately 1 pillar
every 2 miles, demarcate the boundary.
The alignment of the boundary is shown correctly on three map series pub-
lished by the Service Geographique de l'Indochine: the Carte de l'Indochine
1:100.000, Indochine -- Carte de la Frontiare du Nord-Guest at 1:200,000, and
Indochine -- Carte de la Frontiers du Nord-Est, also at 1:200,000. Chinese
maps delineate the boundary in the same manner.
Laos ?Chins Boundary
The boundary between Laos and China was delimited by the 1895 treaty
between China and France that delimited the western segment of the North
Vietnam - China boundary. Demarcation of the boundary was effected after the
signing of the treaty, and currently there is no dispute concerning its lo-
cation.
The bonnaary measures 263.8 miles and is delimited by drainage divides of
the Ylinnan Plateau region of China and northern Laos. It extends through very
mountainous terrain, which is sparsely settled by tribal minorities. Only 15
pillars are used to demarcate its entire length.
The alignment of the boundary is shown correctly on map sheets of the
French-produced Indochine - Carte de la Frontiere du Nord-Ouest at 1:200,000
and on Army Map Service Series 1,5o9 at 1:250,000. Chinese maps show the
boundary in the same manner.
Isms-43areesBounaraz
The Laos - Burma boundary was delimited in 1896 by an agreement between
France and Great Britain. Because it follows the thalweg of a river, the
boundary is regarded as demarcated. It is not in dispute.
The boundary is 147.6 miles in length and is aligned along the thalweg
of the Mekong from the Chinese frontier to the confluence with the Ham Hkok
at the trijunction of Laos, Burma, and Thailand. Although the boundary is
defined precisely, a problem could conceivebly arise over determination of
the precise thalweg in stretches of the Mekong where rapids prevent navi-
gation.
French and British maps agree in their representation of the boundary;
sheets of the British 1-inch (1:63,360) series, Burma - Southern Shan States,
show it in the greatest detail. The Army Map Service Series U542 at 1:250,000
is accurate within the limitations of its smaller scale.
Lass?inhaiketelJ9oundomm
The Laos - Thailand boundary was delimited by a series of treaties between
France and Thailand during the period 1893-1946. It is defined in terns of
physical features through and over which it passes. Although the land sec-
tors of the boundary have not been demarcated, they are not disputed.
The boundary extends for a distance of about 1,090 miles from its inter-
section with the Burmese boundary in the north to its intersection with the
Cambodian boundary in the south. From the trijunction of Laos, Thailand,
and Burma the boundary follows the thalweg of the Mekong River for 59 miles.
At approximately 20010'N 100036'S it leaves the river and follows the moun-
tain range west of the Nam Khop (river) system for about 286 males. This
section of the, bovadary forms tiajT,eislieg*Gfenatitiletigiat of
Sayaboury, which is separated from main p o moo y e hong River.? '
From about 1704410 98.39'E the boundary extends northeastward 86 miles along
the thalweg of the Nam Seung to its junction with the Yekong River.
Over the next 541 miles the boundary is defined, where no islands exist,
by the thalweg of the Mekong River or, where there are islands, by the
"thalweg" closest to the Thai shore. Since seasonal variation in the level
of the Mekong River is great, at tines of low water many of the islands
become attached or nearly attached to the Thai shore. The convention that
delimited this segment of the boundary used the criterion of separation
from shore at the highest water level. Thus, all islands in the sector
belong to Laos.
Approximately 5 miles east of the confluence of the Mekong River with the
Mae Nem Run the boundary leaves the former river and follows the drainage
divide between the two rivers for a distance of 118 miles until it meets the
Cambodian boundary at the Col de Fresh Chambot. Thus, the Province of Chem-
passak and the western portion of Sithandone Province, in the extreme south-
western pert of Laos, like Sayaboury Province, are separated faKm the remain-
der of Laos by the Mekong River, and in these areas the boundary between
Thailand is a land boundary. The situation originated in the agreements of
1893 and 1902 between Siam and France. In the 1893 agreement Siam renounced
rights to the territories on the left bank of the Mekong River as well as to
ail islands in the river. In the 1902 agreement Siam ceded to Laos the terri-
tory that new comprises Sayaboury Province in northwestern Laos as well as
the territory in southwestern Laos that now comprises Champassak Province and
part of Sithandone Province. In 1941 Japan forced France to return the Lao-
tian territories west of the Mekong River to Thailand,but the 1946 Washington
Accord between France and Thailand restored the boundary established by the
1902 Convention.
The two land segments of the boundary are shown on the 11-sheet nap series
at 1:200,000 entitled Commission de Delimitation Entre l'Indo-Chine et le Siam,
published in 1907. For the Mekong River boundary segment, sheets of the Trace
de la Frontiere Franco-Siamoise du Mekong 1/25,000, by the Haute Commission
Permanents Franco-Siamoise de Delimitation du Mekong, 1931, show a boundary
alignment that conforms with the agreements between Siam and Indochina.
Cantthedia-77wzilandBoandarz
The boundary between Cambodia and Thailand was delimited by a series of
agreements between France and Thailand during the period when Canbodia was
under French control. Part of the boundary is demarcated. No disputes over
precise boundary alignment have been raised by either country since the 1962
Judgnent of the ICJ acknowledging Cambodian sovereignty over the Preah Vihear
Temple area (see Map 51019). Cambodia, however, has demanded that Thailand
at an international conference accept the validity of the treaties with
France and the ICJ decision of 1962. Thailand, while willing to accept the
status quo on a de facto basis, has refused to accept it by means of refer-
ence to the ICJ decision, concerning which it continues to maintain rather
ve,gue reservations.
The boundary extends from its intersection with the Laotian boundary at
the Col de fresh Chambot approximately 500 miles westward and than southward
to the Gulf of Siam. For most of its length it is aligned along drainage
divides including the long east-west section of the drainage divide along
the Dangrek escarpment, as well as the 103-mile segment of the drainage di-
vide'of the Chaim des Cardamomes and their extension northward from the
Gulf of Siam. Between these two segments, the boundary follows various
streams and straight lines.
Of the treaties between France and Thailand that define the Cambodia -
Thailand boundary, those of 1904 and 1907 are most important. The 1904 con-
vention between France and Siam delimited the segment of the boundary along
the Dangrek escarpment east of 1040E. The 1907 agreement delimited the re-
mainder of the border, from 104nE westward along the Dangrek escarpment and
then southward to the Gulf of Siam. Only the north-south segment extending
to the gulf is denexcated.
The boundary alignment is shown correctly on seven maps at 1:200,000 com-
piled by the delimitation commissions of 1904 and 1907. Encept for generally
minor changes, the most recently compiled sheets of the series Carte de l'Indo-
chine 1:100.000, published by the Service Geographique de 1' Indochina, show
a boundary alignment identical to that of the commission maps.
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SUBJECT,
1 April 1965
R St/P/C
Classification and Control of Source Materials -
CIA/RR GM 65-2, Internatignal BcundarJets of
Laglitut, dated April 1965
I certify that souroe materials used in CIA/RR GM 65-2,
Ipternati ilm?ougdaries of 4ndochina, dated April 1965, were
olassified no higher than SECRET and were not restricted by
dissemination controls
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