List of sets of four countries that border one another

The typical case: one country surrounded by three others

This is a list of sets of at least four countries that border one another. In the typical case, three countries that border one another form a ring around a landlocked fourth. Paraguay, Luxembourg, Burundi, and Malawi are at the centers of such configurations.

No more than four contiguous countries can share borders, since the complete graph $K 5$ is not planar. On the other hand, non-contiguous countries that have exclaves and dependent territories may form sets of five or more.

As of the 2006 breakup of the State Union of Serbia and Montenegro, there are at least twelve four-country sets in the world in which each country shares a boundary (land or fresh water) with the others.

South America

Paraguay-Brazil-Argentina-Bolivia

Paraguay (red), Brazil (blue), Argentina (green), and Bolivia (magenta)

This set has existed since the early-mid 19th century. In the early 19th century all that existed was the Spanish Viceroyalty of the Río de la Plata and the Portuguese colony of Brazil. With the independence of Argentina (revolution in 1810, fully achieved 1816) and Paraguay (1811) the four-border set began to emerge, and was consolidated by the Brazilian and Bolivian independence (1822 and 1825, respectively).

Borders (km)
Paraguay	-	1290	1880	750
Brazil	1290	-	1224	3400
Argentina	1880	1224	-	832
Bolivia	750	3400	832	-

Eastern Europe

Belarus-Latvia-Lithuania-Russia

This set has existed since the 1991 Dissolution of the Soviet Union. The Russian Kaliningrad Oblast, an exclave on the Baltic Sea, creates a Russian border with Lithuania. Belarus and Latvia share boundaries with both mainland Russia and Lithuania.

Borders (km)
Belarus	-	171	502	959
Latvia	171	-	576	292
Lithuania	502	576	-	227
Russia	959	292	227	-

Belarus-Lithuania-Poland-Russia

Belarus (magenta), Lithuania (blue), Poland (green), and Russia (red)

This set has existed since the 1991 Dissolution of the Soviet Union.

The Russian Kaliningrad Oblast, an exclave on the Baltic Sea, creates Russian borders with both Lithuania and Poland. Belarus does not border Kaliningrad, but has borders with mainland Russia, Lithuania, and Poland.

Borders (km)
Belarus	-	502	407	959
Lithuania	502	-	91	227
Poland	407	91	-	206
Russia	959	227	206	-

Belarus-Poland-Russia-Ukraine

This set has existed since the 1991 Dissolution of the Soviet Union.

The Russian Kaliningrad Oblast, an exclave on the Baltic Sea, creates a Russian border with Poland.

Borders (km)
Belarus	-	407	959	891
Poland	407	-	227	428
Russia	959	227	-	1576
Ukraine	891	428	1576	-

Western Europe

Belgium-Germany-Netherlands-France

Germany (green) and Belgium (red), France (blue) and the Kingdom of the Netherlands (magenta)

This set has existed since the 1830 Independence of Belgium. Even though the German lands have had many territorial changes, Prussia's Rhine Province and later the various unified German states have always bordered the other three countries.

The only land boundary between the Kingdom of the Netherlands and France is on the Caribbean island of Saint Martin (Sint Maarten), where the Netherlands Antilles meets the French Overseas Collectivity of Saint Martin.

Borders (km)
Belgium	-	167	450	620
Germany	167	-	577	451
Netherlands	450	577	-	10
France	620	451	10	-

Luxembourg-France-Germany-Belgium

Luxembourg (red), France (blue), Germany (green), and Belgium (magenta)

This set has existed since the 1839 independence of Luxembourg.

Borders (km)
Luxembourg	-	73	138	148
France	73	-	451	620
Germany	138	451	-	167
Belgium	148	620	167	-

Southeastern Europe

Bosnia and Herzegovina-Serbia-Montenegro-Croatia

Bosnia and Herzegovina (red), Serbia (blue), Montenegro (green), and Croatia (magenta)

This set has existed since the 2006 independence of Montenegro.

Bosnia and Herzegovina has 20 km of coastline on the Adriatic Sea while Croatia borders Montenegro only through the non-contiguous southern portion of the Dubrovačko-neretvanska county, which is an exclave connected to the rest of Croatia only by territorial waters.

Borders (km)
Bosnia and Herzegovina	-	302	225	932
Serbia	302	-	203	241
Montenegro	225	203	-	25
Croatia	932	241	25	-

Caucasus

Azerbaijan-Armenia-Turkey-Iran

Azerbaijan (red), Armenia (green), Turkey (magenta), and Iran (blue)

This set has existed since the 1991 Dissolution of the Soviet Union. Azerbaijan has a border with Turkey through its exclave of Nakhichevan.

Borders (km)
Azerbaijan	-	787	9	611
Armenia	787	-	268	35
Turkey	9	268	-	499
Iran	611	35	499	-

Azerbaijan-Armenia-Georgia-Turkey

This set has existed since the 1991 Dissolution of the Soviet Union. Azerbaijan has a border with Turkey through its exclave of Nakhichevan.

Borders (km)
Azerbaijan	-	787	322	9
Armenia	787	-	164	268
Georgia	322	164	-	252
Turkey	9	268	252	-

Africa

Burundi-Rwanda-Tanzania-Democratic Republic of the Congo

Burundi (green), Rwanda (red), Tanzania (blue), and DR Congo (magenta)

This set has existed since the 1962 change of the united Belgian colony of Ruanda-Urundi into the independent states of Burundi and Rwanda. Congo had achieved independence in 1960 and was followed the next year by Tanganyika, which would later merge with Zanzibar to form Tanzania. The border between DR Congo and Tanzania is entirely aquatic; the two countries are separated by Lake Tanganyika.

Borders (km)
Burundi	-	209	451	233
Rwanda	209	-	217	217
Tanzania	451	217	-	459
Democratic Republic of the Congo	233	217	459	-

Rwanda-Uganda-Democratic Republic of the Congo-Tanzania

Rwanda (red), Uganda (green), DR Congo (magenta), and Tanzania (blue)

By the time of Ugandan independence in 1962, all of the borders of this set were already established. DR Congo and Tanzania are separated by Lake Tanganyika.

Borders (km)
Rwanda	-	169	217	217
Uganda	169	-	765	396
Democratic Republic of the Congo	217	765	-	459
Tanzania	217	396	459	-

Malawi-Mozambique-Zambia-Tanzania

Malawi (red), Mozambique (magenta), Zambia (green), and Tanzania (blue)

This set has existed since the 1964 independence of Zambia and Malawi. Mozambique became independent from Portugal in 1975.

Borders (km)
Malawi	-	1569	837	475
Mozambique	1569	-	419	756
Zambia	837	419	-	338
Tanzania	475	756	338	-

Near misses

The 40 km border between China's Xinjiang Autonomous Region and Russia's Altai Republic prevents Mongolia, Kazakhstan, Russia, and the People's Republic of China from forming a set of four countries that border one another.

The short border between Sikkim in India and Tibet in the People's Republic of China prevents the group Bhutan, India, Nepal and the People's Republic of China from forming such a set.

The 100 m border between Zambia and Botswana at Africa's "four corners" is all that prevents the group Botswana-Namibia-Zimbabwe-Zambia from satisfying the criteria of four countries that border one another (see International quadripoints for more information).

Former border sets of at least four countries

The first two sets below include boundaries shared by former colonial empires (specifically territorial claims in South America, Africa, India, Europe, and the East and West Indies), and thus do not reflect continuous areas of land. In the third one it is referred to Nazi Germany after its annexation of Austria.

Countries	From	To	Terminal Event
France¹, Dutch Republic², Spain³, Portugal⁴, Great Britain⁵	1704	1713	Signing of the Treaty of Utrecht on 11 April 1713
Belgium⁶, Portugal⁷, German Empire⁸, France⁹, United Kingdom¹⁰, Netherlands¹¹	late 19th century	1914	Outbreak of World War I
France, Germany, Italy, Switzerland	1938	1945	The dissolution of Germany into allied occupation zones¹²
Burma, China, India, Pakistan¹³	1947	1971	Independence of Bangladesh

Notes

^ Between 1704 and 1713, France and her colonies neighbored the Netherlands (on Saint Martin), Spain (in Europe), Portugal (between French Guyana and Portuguese Brazil) and Great Britain (between the Indian settlements of Hughli and Chandernagar).
^ Between 1704 and 1713, the Netherlands and her colonies neighbored France (on Saint Martin), Spain (in Europe between Dutch Republic and the Spanish Netherlands), Portugal (between Dutch Suriname and Portuguese Brazil), and Great Britain (between the Indian settlements of Pulicat and Madras.
^ Between 1704 and 1713, Spain and her colonies neighbored France (in Europe), the Netherlands (in Europe between Spanish Netherlands and the Dutch Republic), Portugal (in Europe and South America), and Great Britain (with the 1704 British capture of Gibraltar).
^ Between 1704 and 1713, Portugal and her colonies neighbored France (between Portuguese Brazil and French Guyana), the Netherlands (between Brazil and Dutch Suriname), Spain (in Europe and South America), and Great Britain (between the Indian settlements of Daman and Diu and Surat).
^ Between 1704 and 1713, the Kingdom of Great Britain (and prior to the 1707 Acts of Union, the Kingdom of England) and her colonies neighbored France (between the Indian settlements of Chandernagar and Hughli), the Netherlands (between the Indian settlements of Madras and Pulicat), Spain (with the 1704 British capture of Gibraltar), and Portugal (between the Indian settlements of Daman and Diu and Surat)
^ European Belgium bordered France, the Netherlands, and Germany. The Belgian Congo bordered Portuguese Angola and several French and British colonies in Africa.
^ European Portugal bordered Spain. In 1914, the African colonies of Mozambique, Angola, and Guinea-Bissau bordered territories held by Germany (Namibia and Tanganyika), Great Britain, France, and Belgium. The colony of Timor Leste bordered the Dutch East Indies.
^ Immediately prior to World War I, European Germany bordered the Netherlands, Belgium, and France. African colonies shared boundaries with territories held by Great Britain, Portugal, France, and Belgium
^ European France shared borders with Belgium and Germany. Vast French holdings in colonial Africa abutted colonies possessed by Great Britain, Belgium, Germany, and Portugal. In South America, French Guyana bordered Dutch Suriname.
^ British colonies in Africa shared boundaries with territories held by France, Belgium, Germany, and Portugal. In South America, British Guyana bordered Dutch Suriname.
^ The European Netherlands shared borders with Germany and Belgium. The Dutch East and West India Companies controlled territories that bordered colonies of Portugal (on the island of Timor), Great Britain (Guyana), and France (French Guyana).
^ Date of dissolution assumes that France continued to exist, and include the Occupied Zones, after June 1940; this phrasing ignores the de facto existence of the Italian Social Republic from 1943 on, which was adjacent to the other three states until its last days. The exact date at which a new Austria came into existence may be debatable.
^ From 15 August 1947 to 16 December 1971, Pakistan included modern-day Bangladesh (known as East Pakistan)

Sources

CIA World Factbook CIA World Factbook (public domain)

[0] Between 1704 and 1713, France and her colonies neighbored the Netherlands (on Saint Martin), Spain (in Europe), Portugal (between French Guyana and Portuguese Brazil) and Great Britain (between the Indian settlements of Hughli and Chandernagar).

[1] Between 1704 and 1713, the Netherlands and her colonies neighbored France (on Saint Martin), Spain (in Europe between Dutch Republic and the Spanish Netherlands), Portugal (between Dutch Suriname and Portuguese Brazil), and Great Britain (between the Indian settlements of Pulicat and Madras.

[2] Between 1704 and 1713, Spain and her colonies neighbored France (in Europe), the Netherlands (in Europe between Spanish Netherlands and the Dutch Republic), Portugal (in Europe and South America), and Great Britain (with the 1704 British capture of Gibraltar).

[3] Between 1704 and 1713, Portugal and her colonies neighbored France (between Portuguese Brazil and French Guyana), the Netherlands (between Brazil and Dutch Suriname), Spain (in Europe and South America), and Great Britain (between the Indian settlements of Daman and Diu and Surat).

[4] Between 1704 and 1713, the Kingdom of Great Britain (and prior to the 1707 Acts of Union, the Kingdom of England) and her colonies neighbored France (between the Indian settlements of Chandernagar and Hughli), the Netherlands (between the Indian settlements of Madras and Pulicat), Spain (with the 1704 British capture of Gibraltar), and Portugal (between the Indian settlements of Daman and Diu and Surat)

[5] European Belgium bordered France, the Netherlands, and Germany. The Belgian Congo bordered Portuguese Angola and several French and British colonies in Africa.

[6] European Portugal bordered Spain. In 1914, the African colonies of Mozambique, Angola, and Guinea-Bissau bordered territories held by Germany (Namibia and Tanganyika), Great Britain, France, and Belgium. The colony of Timor Leste bordered the Dutch East Indies.

[7] Immediately prior to World War I, European Germany bordered the Netherlands, Belgium, and France. African colonies shared boundaries with territories held by Great Britain, Portugal, France, and Belgium

[8] European France shared borders with Belgium and Germany. Vast French holdings in colonial Africa abutted colonies possessed by Great Britain, Belgium, Germany, and Portugal. In South America, French Guyana bordered Dutch Suriname.

[9] British colonies in Africa shared boundaries with territories held by France, Belgium, Germany, and Portugal. In South America, British Guyana bordered Dutch Suriname.

[10] The European Netherlands shared borders with Germany and Belgium. The Dutch East and West India Companies controlled territories that bordered colonies of Portugal (on the island of Timor), Great Britain (Guyana), and France (French Guyana).

[11] Date of dissolution assumes that France continued to exist, and include the Occupied Zones, after June 1940; this phrasing ignores the de facto existence of the Italian Social Republic from 1943 on, which was adjacent to the other three states until its last days. The exact date at which a new Austria came into existence may be debatable.

[12] From 15 August 1947 to 16 December 1971, Pakistan included modern-day Bangladesh (known as East Pakistan)

1

2

3

4

5

6

7

8

9

10

11

12

13