What Is Condominium In International Law?

The Moselle River, which Germany and Luxembourg both exercise control over in a modern-day example of condominium.
The Moselle River, which Germany and Luxembourg both exercise control over in a modern-day example of condominium.

Regarding international law, "condominium" refers to territory that is governed by multiple sovereign powers who have formally agreed to share duties without necessarily dividing the area into national zones. Despite the recognition of a condominium as a theoretical possibility, the idea has been rare in practice. Complications often arise in regards to maintaining mutual collaboration between countries. If the mutual understanding fails, the situation then most likely becomes untenable. The recording for the term condominium in English dates back to 1714.

Examples Of Current Condominia

Throughout history, many condominia have been established in different places throughout the world. Germany, Austria, and Switzerland consider themselves as holders of a triple condominium over Lake Constance's main part. However, there exists no international treaty that establishes where the three countries have their borders around Lake Constance. Germany and Luxembourg hold a condominium over the Moselle River together with its tributaries and the Our and Sauer. The condominium also includes the tip of an island that is located near Schengen, 15 river islands of different sizes and bridges. The condominium between the two countries was established through a treaty in 1816. The Brčko District which is located in Bosnia and Herzegovina holds a condominium between Republika Srpska and the Federation of Bosnia and Herzegovina. Honduras, Nicaragua and El Salvador hold a tridominium over regions of the Gulf of Fonseca together with the territorial sea beyond its mouth. Pheasant Island, which is also known as Conference Island, is located in the River Bidassoa and forms a condominium which was established in 1659, through the Treaty of the Pyrenees.


Co-principality has also been known as "coregency". It was traditionally an arrangement where a monarchial position which is ordinarily held by one person is held by two or more persons. UnderFrench law, Andorra was regarded as a French - Spanish condominium. However, this type of arrangement is most commonly classified as a co-principality because it is a sovereign state instead of a possession owned by one or more sovereign powers. The Head of State position is shared by two approved foreigners. One of them is the French president currently François Hollande while the other Bishop of Urgell in Spain currently Joan Enric Vives Sicilia.

Examples Of Former Condominia

Between 1941 and 1943, the independent state of Croatia formed a condominium between Fascist Italy and Nazi Germany. The condominium only lasted until 1943 when the Italian Fascist regime collapsed. The US and British held a condominium over the Canton and Enderbury Islands between 1939 and 1979 when the two islands became a part of Kiribati. Spain and Portugal held a condominium over Cauto Misto until 1864. The nation of Egypt formed a condominium between France and the United Kingdom from 1876 to 1882.

Examples Of Proposed Condominia

Following years of dispute, the Danish and Canadian governments came close to declaring Hans Island a condominium. However, another alternative was proposed which involved dividing the island in half, but negotiations still continued. There has been a hypothetical condominium proposed between Palestine over Jerusalem. However, the condominium was to be within the Palestinian independence framework. During a proposal for the Partition of Belgium, Wallonia and Flanders held a condominium over Brussels. There are plenty of other proposed condominia that are yet to be confirmed.


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