List of divided islands
The vast majority of islands in the world are either a country in their own right or part of a larger country. This is a list of those few islands whose land is divided between two or more countries or territories by an international border. In many cases (e.g. Ireland, Cyprus, Timor) the division has been the source of much dispute.
Divided among three countries
- Borneo - Among
Indonesia (70%), 
Malaysia (25%), and 
Brunei (5%) - Cyprus - see below
- Island in the Moselle River near Schengen: mostly in
France, the tip is in the Moselle condominium shared by 
Luxembourg and 
Germany[1] - Treriksröset - the boundary cairn at the tripoint of
Norway, 
Sweden and 
Finland is 10 metres from the shore of Lake Goldajärvi/Koltajauri, and hence arguably a tiny artificial island.
Divided between two countries
Sea islands
- New Guinea - Between Indonesia (50%) and
Papua New Guinea (50%) - Ireland - Between the
Republic of Ireland (83%) and the 
United Kingdom (Northern Ireland; 17%) - Hispaniola - Between the
Dominican Republic (67%) and 
Haiti (33%) - Isla Grande de Tierra del Fuego - Between
Chile (50%) and 
Argentina (50%) - Timor - Between Indonesia and
East Timor - Cyprus - De jure between the
Republic of Cyprus (97%) and the United Kingdom (controlling the UK sovereign bases of Akrotiri and Dhekelia; 3%) - de facto there is also the unrecognized
Turkish Republic of Northern Cyprus in the part of the island militarily occupied by 
Turkey (de facto 36%), together with a 
United Nations administered buffer zone (de facto 1%), separating the part controlled by the government of the Republic of Cyprus (de facto 61%) from the Turkish-occupied part. The remaining is occupied by the UK sovereign bases of Akrotiri and Dhekelia (de facto 2%)
- de facto there is also the unrecognized
- Sebatik Island - Between Indonesia and Malaysia
- two islands situated between Sir Creek and Kori Creek are divided between India and Pakistan
- Usedom/Uznam - Between Germany (84%) and
Poland (16%) - Saint Martin (Saint-Martin/Sint Maarten) - Between the Collectivity of Saint Martin (61%) and the
Netherlands Antilles (an autonomous part of the 
Kingdom of the Netherlands; 39%) - Kataja (including Inakari) in the Gulf of Bothnia between Finland and Sweden.[2]
- Artificial island on the King Fahd Causeway - between
Saudi Arabia and 
Bahrain. - Märket - Between the autonomous Finnish province of
Åland (50%) and Sweden (50%). The world's smallest divided sea island.
Lake islands
- Between
United States and 
Canada: - Province Island in Lake Memphremagog, between Quebec (91%) and Vermont (9%) [3]
- Two islands in Boundary Lake, between North Dakota and Manitoba.
- Between Finland and
Russia: - Äikkäänniemi in Nuijamaanjärvi[4]
- Suursaari and a smaller island in Yla-Tirja[5]
- Tarraassiinsaari, Härkäsaari, and Kiteensaari in Melaselänjärvi[6][7]
- Rajasaari in Kokkojärvi[8]
- Kalmasaari in Vuokkijärvi[9]
- Varposaari in Hietajärvi[10]
- Parvajärvensaari in Parvajärvi[11]
- Keuhkosaari in Pukarijärvi / Ozero Pyukharin[12][13]
- Siiheojansuusaari and Tossensaari in Onkamojärvi / Ozero Onkamo[14] [15]
- Between Finland and Norway:
- Between Sweden and Norway:[18]
- Hisön/Hisøya in Norra Kornsjön/Nordre Kornsjø[19]
- Kulleholmen/Kalholmen and Tagholm/Tåkeholmen in Södra Boksjön/Søndre Boksjø[20]
- Salholmen, Mosvikøya, and Trollön in Store Le[21]
- Island in Tannsjøen/Tannsjön[22]
- Linneholmene in Helgesjö[23]
- Jensøya in Holmsjøen[24]
- Storøya in Utgardsjøen[25]
- Fallsjøholmen in Fallsjøen (Nordre Røgden)[26]
- Island in Kroksjøen[27]
- Island in Vonsjøen[28]
- Island in Skurdalssjøen/Kruehkiejaevrie[29]
- Island in a lake at altitude 710m on the Gihcijoka river[30]
- Three islands in Čoarvejávri[31]
- Between
Lithuania and 
Belarus: - Sosnovec and another nameless island in Lake Drūkšiai[32][33][34][35]
- Between United Kingdom and Ireland:
- Pollatawny in Lough Vearty.[36]
- Between
Ethiopia and 
Djibouti:
- The border between
Austria and 
Hungary cuts across the Neusiedler See/Fertő tó, where the water level fluctuates, sometimes exposing island flats which straddle the border.
River islands
- Heixiazi/Bolshoy Ussuriyskiy at the confluence of the Ussuri and Amur rivers, between
People's Republic of China and Russia - Corocoro Island in the delta of the Barima River: split between
Venezuela and 
Guyana[38] - San Jose Island, Rio Negro: between
Colombia and 
Brazil. [39] - The lower reaches of the Ganges[40], Teesta[41], and Brahmaputra[42] Rivers, approaching the Ganges Delta, are braided and contain numerous sand islands called chars[43]. These can be large and inhabited but are impermanent. At any given time, several are likely to straddle the border between
India (Assam and West Bengal) and 
Bangladesh, though this border is not fully specified. - An island labelled 'Q' in the Maritsa River, between
Greece and Turkey.[44] - An islet in the Uutuanjoki, between Finland and Norway.[45]
- An islet in the Vadet near Tunnsjø, between Norway and Sweden.[46]
- An islet on the western side of the golf course that straddles the municpalities of Tornio in Finland, and Haparanda in Sweden is crossed by the international border.
Historically divided islands
- Other islands have been divided by an international border in the past but are now unified. Notable examples include:
- Saaremaa and Hiiumaa - Divided between the Livonian Order and the Bishopric of Ösel-Wiek during the Middle Ages
- Great Britain - Divided prior to 1707, when England and Scotland passed the Acts of Union; since then part of the Kingdom of Great Britain/United Kingdom.
- Newfoundland - Divided between England/Great Britain and France until the Treaty of Utrecht in 1713; subsequently British/independent/Canadian
- Saint Kitts - Divided between England/Great Britain and France from 1626 to the Treaty of Utrecht in 1713; subsequently British/Saint Kitts and Nevis. (Both France and Britain occupied the entire island during various wars before and after 1713.)
- Sakhalin - Divided between Imperial Russia/Soviet Union and the Empire of Japan from the Treaty of Portsmouth in 1905 to the Surrender of Japan in 1945; subsequently wholly part of the Soviet Union/Russian Federation. Japan still regards the sovereignty of this island as undetermined, and it is frequently shown on Japanese maps as 'no man's land'.
- Ankoko Island in the Cuyuni River on the border between Venezuela and British Guiana (now Guyana) was shared until Venezuela annexed the eastern half in 1966 as part of an ongoing border dispute.
- Zhongchan Dao in the Pearl River Delta was divided between China and Macau from the Treaty of Tientsin in 1862 until Macao reverted to China in 1999.
- A few former islands have disappeared:
- Vozrozhdeniya Island in the Aral Sea is split between
Uzbekistan and 
Kazakhstan, whose border became an international frontier in 1991 with the dissolution of the Soviet Union. By 2002, the island had become a peninsula owing to the falling water-level in the Aral Sea. - The Bogomerom archipelago in Lake Chad was split between
Chad and 
Nigeria[47]. The water level has always varied, but has now fallen such that this land is now permanently above the shoreline.
- Vozrozhdeniya Island in the Aral Sea is split between
