A condominium (plural either condominia, as in Latin, or condominiums) in international law is a territory (such as a border area or a state) in or over which multiple sovereign powers formally agree to share equal dominium (in the sense of sovereignty) and exercise their rights jointly, without dividing it into "national" zones.
Although a condominium has always been recognized as a theoretical possibility, condominia have been rare in practice. A major problem, and the reason so few have existed, is the difficulty of ensuring co-operation between the sovereign powers; once the understanding fails, the status is likely to become untenable.
The word is recorded in English since 1718, from Modern Latin, apparently coined in Germany c. 1700 from Latin con- 'together' + dominium 'right of ownership' (compare domain). A condominium of three sovereign powers is sometimes called a tripartite condominium or tridominium.
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As an alternative to delimiting their sea boundary, Colombia and Jamaica share a maritime condominium called the Joint Regime Area in the Caribbean Sea by mutual agreement. The outer portion of the EEZ of each country otherwise would overlap in this area. Unlike other "joint development zones", this condominium appears not to have been purposed simply as a way to divide oil, fisheries or other resources.
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The area is administrated jointly by the "Joint Committee for the Concerted Management of the Kourou/Koalou Area" (COMGEC-K). Neither nation expresses sovereignty over the area, with a permanent solution still pending.[6]
Austria and Germany consider themselves to hold a tripartite condominium with Switzerland (albeit on different grounds) over the main part of Lake Constance (without its islands). On the other hand, Switzerland holds the view that the border runs through the middle of the lake.[7][8] Hence, no international treaty establishes where the borders of Switzerland, Germany, and Austria, in or around Lake Constance, lie.[8]
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The Moselle and its tributaries, the Sauer and the Our, constitute a condominium between Germany and Luxembourg, which also includes bridges, about 15 river islands of varying size,[9] and the tip of one island, Staustufe Apach,[10] near Schengen (the rest of the island is in France).
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Officially known as the Australia–Indonesia Memorandum of Understanding, the MOU 74 Box was established by a bilateral agreement regarding the Operations of Indonesian Traditional Fishermen in Areas of the Australian Fishing Zone and Continental Shelf – 1974. The agreement recognizes access rights of traditional Indonesian fishers from Rote Ndao Regency in shared waters to the north of Australia with regard to the long history of traditional Indonesian fishing there, especially for trepang, trochus, abalone and sponges. The MOU 74 Box includes the Ashmore and Cartier Islands, Browse Island, and Scott and Seringapatam Reefs.[11]
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Pheasant Island is an island of the Bidassoa. Established as part of the Treaty of the Pyrenees, It is formally administered by Spain between 1 February and 31 July each year (181 or 182 days) and by France between 1 August and 31 January each year (184 days).[12]
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Tort-Kocho is a road which connects the TajikistaniVorukh exclave in Kyrgyzstan to the rest of Tajikistan. Prior to 2025, both the Kyrgyz and Tajikistani considered the road part of their sovereign territory.[14] The road was contested during the 2021 Kyrgyzstan–Tajikistan clashes when Tajik administrators blocked the Osh–Batken–Isfana road demanding the Tort-Kocho road be unblocked by Kyrgyzstan.[15] As part of the 2025 delimitation of the Kyrgyzstan–Tajikistan border, the Template:Cvt wide roadbed and a Template:Cvt "security zone" were declared neutral territory, with Kyrgyzstani politician Kamchybek Tashiev saying the road will not belong to "either the Kyrgyz or Tajik side".[16]
Co-principality
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In 688 the ByzantineEmperorJustinian II and the UmayyadCaliphAbd al-Malik ibn Marwan reached an unprecedented agreement to establish a condominium (the concept did not yet exist) over Cyprus, with the collected taxes from the island being equally divided between the two parties. The arrangement lasted for some 300 years, even though in the same time there was nearly constant warfare between the two parties on the mainland.[18]
Anglo-Egyptian Sudan was legally an Egyptian-British condominium from 1899 until 1956, although in reality Egypt played no role in its government other than providing some administrators in the country: all political decisions were made by the United Kingdom and all Governors-General of Anglo-Egyptian Sudan were British. The system was resented by Egyptian and Sudanese nationalists, and would later be disavowed by the Egyptian Government, although it persisted due to the United Kingdom's effective control over Egypt itself, which began from 1882 and continued until at least 1936.
A small area (Hadf and surroundings) on the Arabian Peninsula, a part of Oman, at one time was jointly ruled with the Emirate of Ajman, one of the Trucial States and later a member of the United Arab Emirates. The agreement defining the Hadf zone was signed in Salalah on 26 April 1960 by Sultan Said bin Taimur and in Ajman on 30 April 1960 by Shaikh Rashid bin Humaid Al Nuaimi III, ruler of Ajman.[24] This provided for some joint supervision in the zone by the ruler of Ajman and the shaikhs under the rule of Muscat. It allowed the Ajman ruler to continue collecting zakat (Islamic tax). The ruler of Ajman was, however, not to interfere in the affairs of the local people, the Bani Ka'ab (a branch of the Banu Kaab), which were the sole responsibility of shaikhs who were under Muscat rule. The agreement was later terminated.[25]
The Holy Roman Empire hosted numerous condominia within its boundaries. Many princes and especially Imperial knights and counts mortgaged partial ownership or rights within their lands to the Emperor, sometimes in perpetuity. Most of these were located in the Swabian Circle, close to the Emperor's personal domains in Further Austria. Some condominia were shared by lesser princes, especially in cases of inheritances held in common by branches of a princely line. Disputes over condominium contracts were submitted to the Imperial court at Wetzlar, or petitioned to the Emperor himself. Some cases within the Holy Roman Empire included the following:
The City of Bergedorf was a condominium of the Imperial cities of Hamburg and Lübeck, and the terms were extended beyond the Holy Roman Empire's dissolution until 1868, when Lübeck sold its rights in Bergedorf to Hamburg.
The Imperial village of Holzhausen was a partial condominium, two thirds of which was immediate to the Emperor and the remaining third subject to various landlords.
The Samoan Islands from 1889 to 1899 were a rare tripartite condominium under joint protectorate of Germany, the United Kingdom and the United States. It would later become Samoa and American Samoa.
Togoland, formerly a German protectorate, was an Anglo-French condominium, from when the United Kingdom and France occupied it on 26 August 1914 until its partition on 27 December 1916 into French and British zones. The divided Togoland became two separate League of Nations mandates on 20 July 1922: British Togoland, which joined Gold Coast (present-day Ghana) in 1956, and French Togoland, which is now the nation of Togo.
Tangier International Zone, an international zone, was nominally under Moroccan sovereignty but jointly administered by several European powers in 1924. It was returned to full Moroccan sovereignty in 1956.
The term is sometimes applied to a similar arrangement between members of a monarch's countries in (personal or formal) union, as was the case for the district of Fiume (what is today Rijeka, Republic of Croatia), shared between Hungary and Croatia within the Habsburg Empire since 1868.
Between 1913 and 1920 Spitsbergen was a neutral condominium. The Spitsbergen Treaty of 9 February 1920 recognises the full and absolute sovereignty of Norway over all of the Arctic archipelago of Svalbard. The exercise of sovereignty is, however, subject to certain stipulations, and not all Norwegian law applies. Originally limited to nine signatory nations, over 40 are now signatories of the treaty. Citizens of any of the signatory countries may settle in the archipelago. Currently, only Norway and Russia make use of this right.
In 1992, South Africa and Namibia established a Joint Administrative Authority in the enclave of Walvis Bay, prior to its cession to Namibia in 1994.[28]
The Saudi Arabian–Kuwaiti neutral zone was established in 1922 by the Uqair Convention. It was a 2,000 square mile area designed to accommodate the Bedouin people, a nomadic group who regularly crossed through the Saudi and Kuwaiti border. The area was partitioned in 1970 after a 1938 discovery of oil near the zone brought speculation that there may be oil in the condominium.
In 2001, the British government held discussions with Spain with a view to putting a proposal for joint sovereignty to the people of Gibraltar. This initiative was pre-emptively rejected by Gibraltarians in the 2002 referendum.[30][31]
In 2012, the Canadian and Danish governments were close to an agreement to declare Hans Island a condominium, after decades in dispute. In June 2022, the Danish, Greenlandic, Canadian, and Nunavut governments instead decided to divide the island in half.
In the talks between the UK and the People's Republic of China in 1983–84 over the transfer of sovereignty over Hong Kong, one of the British proposals was to transfer the sovereignty of Hong Kong and its dependencies to the People's Republic of China while the UK would retain the rights of administration of the territory.[32] The proposal was rejected and negotiations ended with the UK agreeing to relinquish all rights over Hong Kong to China in 1997.
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↑Jozo Tomasevich. "The Chetniks". War and Revolution in Yugoslavia. Stanford University Press, 1975. p. 103. "The condominium in Croatia was the most important example of Italo-German collaboration in controlling and despoiling an occupied area [...]".
↑Stephen R. Graubard, (ed.).Exit from Communism. Transaction Publishers, 1993. pp. 153–154. "After the Axis attack on Yugoslavia in 1941, Mussolini and Hitler installed the Ustašas in power in Zagreb, making them the nucleus of a dependent regime of the newly created Independent State of Croatia, an Italo-German condominium predicated on the abolition of Yugoslavia." [2]Template:Webarchive
↑Günay Göksu Özdoğan, Kemâli Saybaşılı. Balkans: a mirror of the new international order. Marmara Üniversitesi. Dept. of International Relations, 1995. p. 143. "Croatia (with Bosnia-Hercegovina) formally became a new Axis ally – the
Independent State of Croatia (NDH). This was in fact, Italo-German condominium, [...]".
↑John R. Lampe (ed.), Mark Mazower (ed.). Ideologies and National Identities: The Case of Twentieth-Century Southeastern Europe. Central European University Press, 2003. p. 103. "[...] the Independent State of Croatia (hereafter NDH, Nezavisna Drzava Hrvatska), in reality an Italo-German condominium [...]"
