List of divided islands

This is a list of islands whose land is divided by one or more international borders.

Sea islands

Island	Area km2	Countries (percentage of island's area)
New Guinea	785,753[1]	Indonesia (53.52%) Papua, West Papua  Papua New Guinea (46.48%)
Borneo	748,168[1]	Indonesia (73%) Central Kalimantan, East Kalimantan, South Kalimantan, West Kalimantan  Malaysia (26%) Sabah, Sarawak  Brunei (1%)
Ireland	81,638[1]	Republic of Ireland (83%)  United Kingdom (17%) Northern Ireland
Hispaniola	73,929[1]	Dominican Republic (65%)  Haiti (35%)
(Isla Grande de) Tierra del Fuego	47,992[1]	Chile (56%) Tierra del Fuego  Argentina (44%) Tierra del Fuego
Timor	28,418[1]	Indonesia (53%) East Nusa Tenggara  East Timor (47%)
Cyprus	9,234[1]	De jure  Republic of Cyprus (97%)  United Kingdom sovereign bases of Akrotiri and Dhekelia (3%) De facto  Republic of Cyprus(60%)  Turkish Republic of Northern Cyprus (35%)  United Kingdom sovereign bases of Akrotiri and Dhekelia (3%)  United Nations buffer zone (3%)
Sebatik Island	452.2[1]	Indonesia, East Kalimantan  Malaysia, Sabah
Usedom	445[2]	Germany (79%[2]) Vorpommern-Greifswald  Poland (21%) West Pomeranian Voivodeship
Saint Martin	91.9[1]	France (61%) Saint-Martin, an overseas collectivity  Kingdom of the Netherlands (39%) Sint Maarten, a constituent country
Hans Island [3]	1.3	Canada Nunavut  Kingdom of Denmark Greenland, a constituent country
Kataja (including Inakari)	0.71	Finland  Sweden[4]
Embankment No. 4, King Fahd Causeway	0.66[5]	Saudi Arabia  Bahrain
Märket	0.03	Finland (50%) Åland Islands  Sweden (50%) Uppsala County and Stockholm County
Koiluoto	<0.03	Finland (>50%)  Russia (<50%)[6]

Lake islands

• Among Norway, Sweden and Finland:
  • Treriksröset - the boundary cairn at the tripoint of is 10 metres from the shore of Lake Goldajärvi/Koltajauri, and hence arguably a tiny artificial island. Around 14 m².
• Between the United States and Canada:
  • Province Island in Lake Memphremagog, between Quebec (91%) and Vermont (9%) ^[7]
  • Two islands in Boundary Lake, between North Dakota and Manitoba.
• Between Norway and Russia:
  • In Klistervatn: Store Grenenholmen^[8]
  • In Grensevatn: Korkeasaari and an unnamed islet^[9]
• Between Finland and Russia:
  • Äikkäänniemi in Nuijamaanjärvi^[10]
  • Suursaari and a smaller island in Yla-Tirja^[11]
  • Tarraassiinsaari, Härkäsaari, and Kiteensaari in Melaselänjärvi^[12][13]
  • Rajasaari in Kokkojärvi^[14]
  • Kalmasaari in Vuokkijärvi^[15]
  • Varposaari in Hietajärvi^[16]
  • Parvajärvensaari in Parvajärvi^[17]
  • Keuhkosaari in Pukarijärvi / Ozero Pyukharin^[18][19]
  • Siiheojansuusaari and Tossensaari in Onkamojärvi / Ozero Onkamo^{[20] [21]}
• Between Finland and Norway:
  • Island in Kivisarijärvi/Keđgisualuijävri^[22]
  • Island in lake SE of boundary marker 347A^[23]
• Between Sweden and Norway:^[24]
  • Island in Sör Vammsjön/Vammen Søndre^[25]
  • Hisön/Hisøya in Norra Kornsjön/Nordre Kornsjø (≈0,09 km²)^[26]
  • Kulleholmen/Kalholmen (≈5500 m²) and Tagholm/Tåkeholmen (≈600 m²) in Södra Boksjön/Søndre Boksjø^[27]
  • Salholmen and Trollön in Stora Le/Store Le^[28]
  • Island in Tannsjøen/Tannsjön^[29]
  • Linneholmene in Helgesjö^[30]
  • Jensøya in Holmsjøen^[31]
  • Storøya in Utgardsjøen^[32]
  • Fallsjøholmen in Fallsjøen (Nordre Røgden)^[33]
  • Island in Kroksjøen^[34]
  • Island in Vonsjøen^[35]
  • Island in Skurdalssjøen/Kruehkiejaevrie^[36]
  • Island in a lake at altitude 710m on the Gihcijoka river^[37]
  • Three islands in Čoarvejávri^[38]
• Between Lithuania and Belarus:
  • Sosnovec and another nameless island in Lake Drūkšiai^{[39][40][41][42]}
• Between the United Kingdom and Ireland:
  • Pollatawny in Lough Vearty.^[43]
• Between Ethiopia and Djibouti:
  • Island off Cape Aleilou in Lake Abbe^[44]

• 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

• Island in the Moselle River near Schengen: mostly in France, the tip is in the Moselle condominium shared by Luxembourg and Germany^[45]
• Bolshoy Ussuriyskiy (Heixiazi) at the confluence of the Ussuri and Amur rivers, between the People's Republic of China and Russia^[46].
• Bolshoy (Abagaitu) at the Argun River, between the People's Republic of China and Russia^[46].
• Corocoro Island in the delta of the Barima River: split between Venezuela and Guyana^[47]
• San Jose Island, Rio Negro: between Colombia and Brazil. ^[48]
• The island complex Martín García - Timoteo Domínguez in the Río de la Plata between Argentina and Uruguay. ^[49]
• The lower reaches of the Ganges^[50], Teesta^[51], and Brahmaputra^[52] Rivers, approaching the Ganges Delta, are braided and contain numerous sand islands called chars^[53]. 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.^[54]
• An islet in the Uutuanjoki, between Finland and Norway.^[55]
• An islet in the Vadet near Tunnsjø, between Norway and Sweden.^[56]
• An islet on the western side of the golf course that straddles the municipalities of Tornio in Finland, and Haparanda in Sweden is crossed by the international border.^{[citation needed]}
• An islet in the Euphrates River on the border of Iraq and Syria.

Historically divided islands

Other islands have been divided by an international border in the past but are now unified.

The definite borders of modern nation-states do not apply in other forms of societal organisation, where "divided" islands may consequently be less noteworthy. For example, in Ancient Greece, the island of Euboea was divided among several city states, including Chalcis and Eretria; and prior to European settlement, Tasmania was divided between nine indigenous tribes.

Islands in wartime may be divided between an invading and defending power, as with Crete in 1645–69 between the Ottoman Empire and the Republic of Venice.

Examples of formerly divided islands include:

• Corsica - divided between Pisa and Genoa from an edict of Pope Innocent II in 1132 till the Battle of Meloria in 1284; subsequently part of Genoa, Aragon, Genoa again, the Corsican Republic, and France
• Sardinia - divided into indigenous giudicati from before 900 till the extinction of Arborea in 1420; since when it has been part of Aragon, Spain, Piedmont-Sardinia, and Italy.
• Saaremaa (1237-1570) and Hiiumaa (1254-1563) - Divided between the Livonian Order and the Bishopric of Ösel-Wiek (Denmark after 1560) Subsequently they were part of Denmark (Saaremaa only), Sweden, Imperial Russia, Estonia, the Soviet Union, and Estonia again.
• Tobago - from 1654-1659 had colonies from both Courland and the Netherlands, though both soon failed.^[57] Later part of France, Great Britain/United Kingdom, and Trinidad and Tobago.
• Ternate - divided between Spain allied with Tidore and the Netherlands allied with the Sultan of Ternate from 1607 to 1663. Later Dutch and Indonesian.
• Long Island - divided between the Netherlands and England from 1640 (de facto: the founding of Southold) or 1650 (de jure: the Treaty of Hartford) to the surrender of New Netherland in 1664; subsequently English/British and United States.
• 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.)
• Elba - divided from 1548 to 1802. Portoferraio belonged to the Duke of Florence (later the Grand Duchy of Tuscany) from 1548 till ceded to France in 1802 under the Treaty of Amiens. Porto Longone belonged to the State of Presidi, a client of first Spain and then the Kingdom of Naples, from 1557 till ceded to France in 1801 by the Treaty of Florence. The rest of the island belonged to the Principality of Piombino till conquered by France, which in 1802 made the entire island part of the Kingdom of Etruria. It was subsequently part of France, Piombino under Elisa Baciocchi, under the sovereignty of Napoleon by the Treaty of Fontainebleau, part of Tuscany again, and finally part of Italy.^[58][59]
• Efate - Divided for several months in 1889 between Franceville and the New Hebrides, then under an Anglo-French joint naval commission.
• Sakhalin - Divided between Imperial Russia/Soviet Union and the Empire of Japan by 50th parallel north 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'.
• Killiniq Island - divided between Canada and the Colony/Dominion of Newfoundland from the Foundation of Canada in 1867 to its union with Newfoundland in 1949.
• Ankoko Island in the Cuyuni River on the border between Venezuela and British Guiana (now Guyana).
• Zhongshan 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^[60]. The water level has always varied, but has now fallen such that this land is now permanently above the shoreline.

See also

• Condominium (international law) - land jointly administered by two states, rather than divided between them (e. g., Pheasant Island, administered by France and Spain during alternating periods of six months).
• Category:Disputed islands and list of territorial disputes - includes many islands claimed by multiple countries, but administered by one.
• Guantanamo Bay Naval Base - leased indefinitely by the United States but with sovereignty retained by Cuba
• Korean Demilitarized Zone - includes several small islands
• List of islands in lakes

References

1. ^ ^{a b c d e f g h i} "Islands by land area". UN system-wide Earthwatch. United Nations Environment Programme. 1998-02-18. http://islands.unep.ch/Tiarea.htm. Retrieved 2009-09-27. 
2. ^ ^{a b} Margedant, Udo; Thomas Ellerbeck (1991) (in German). Politische Landeskunde Mecklenburg-Vorpommern. Mecklenburg-Vorpommern: Landeszentrale für politische Bildung. p. 89. 
3. ^ A territorial dispute. Both states previously claimed the entirety of the island. In 2008, Canada adjusted its border to claim the western half of the island only.
4. ^ Map of Inakari, the Finnish part of Kataja 65°41′59″N 24°10′08″E / 65.699644°N 24.168781°E / 65.699644; 24.168781
5. ^ "Border Station". King Fahd Causeway. King Fahd Causeway Authority. http://www.kfca.com.sa/cause_border.htm. Retrieved 2009-09-27. 
6. ^ Map of Koiluoto, the Finnish part of Koiluoto 60°30′21″N 27°46′21″E / 60.50575°N 27.772472°E / 60.50575; 27.772472
7. ^ Jacques Boisvert. "Province Island". http://magogquebec.homestead.com/files/province_island.html. Retrieved 2006-11-04. "It is the largest island in Lake Memphremagog, being 77 acres, of which 7 acres, are in the United States." 
8. ^ "Norway-Russia Boundary Map: Boundary markers 167 - 177: Sandneset-Klistervatn" (in Norwegian/Russian). Norwegian Boundary Commission for the Norway-Russia border. http://www.grensekom.no/grensekart%20167-177.php. Retrieved 2007-09-25.  — boundary markers #169-172
9. ^ "Norway-Russia Boundary Map: Boundary markers 7 - 14: Grenseberg-Ødevasselva" (in Norwegian/Russian). Norwegian Boundary Commission for the Norway-Russia border. http://www.grensekom.no/grensekart%207-14.php. Retrieved 2007-09-25.  — boundary markers #12-13 (Korkeasaari) & #14 (unnamed islet) )
10. ^ Portion of Nuijamaanjärvi with Äikkäänniemi marked from Citizen's Mapsite of Finland.
11. ^ Portion of Yla-Tirja with divided islands at markers 93 (Suursaari) and 94 (smaller island) from Citizen's Mapsite of Finland.
12. ^ Portion of Melaselänjärvi showing Tarraassiinsaari and Härkäsaari from Citizen's Mapsite of Finland.
13. ^ Portion of Melaselänjärvi showing Kiteensaari from Citizen's Mapsite of Finland.
14. ^ Portion of Kokkojärvi showing Rajasaari from Citizen's Mapsite of Finland.
15. ^ Portion of Vuokkijärvi showing Kalmasaari from Citizen's Mapsite of Finland.
16. ^ Portion of Hietajärvi showing Varposaari from Citizen's Mapsite of Finland.
17. ^ Portion of Parvajärvi showing Parvajärvensaari from Citizen's Mapsite of Finland.
18. ^ Office of the Geographer, Bureau of Intelligence and Research (1967-02-01) (PDF). International Boundary Study No. 74: Finland - U.S.S.R. boundary. United States Department of State. p. 21. http://www.law.fsu.edu/library/collection/LimitsinSeas/IBS074.pdf. "Hence the frontier runs...to a point on a small unnamed island in Lake Pukarinjarvi between the cape west of the village of Laitela and the Niittysaaryi island." 
19. ^ Portion of Pukarijärvi with Keuhkosaari marked from Citizen's Mapsite of Finland.
20. ^ International Boundary Study No. 74, page 22. ""The frontier follows the creek down to Lake Onkamojarvi, intersects the small island of Siiheojansuusaai and proceeds in a straight line to the small island of Tossensaari."
21. ^ Portion of Onkamojärvi from Citizen's Mapsite of Finland (Siiheojansuusaari is IV/179; Tossonsaari is IV/180)
22. ^ Portion of Kivisarijärvi with divided island marked from Citizen's Mapsite of Finland. 69°44′09″N 28°52′56″E / 69.735926°N 28.88235°E / 69.735926; 28.88235
23. ^ Neighborhood of boundary marker 347A, with divided island marked from Citizen's Mapsite of Finland. 69°53′N 28°18′E / 69.89°N 28.3°E / 69.89; 28.3
24. ^ Verified at Norwegian state cartographic agency website (English) (Norwegian) (Sami)
25. ^ 58°53′18″N 11°27′27″E / 58.88843°N 11.45739°E / 58.88843; 11.45739
26. ^ Hisøya: 58°54′22.8″N 11°39′7.1″E / 58.906333°N 11.651972°E / 58.906333; 11.651972
27. ^ Søndre Boksjø: 59°02′N 11°42′E / 59.03°N 11.7°E / 59.03; 11.7
28. ^ Salholmen: 59°14′15.95554″N 11°49′32.23645″E / 59.2377654278°N 11.8256212361°E / 59.2377654278; 11.8256212361; Trollön: 59°15′17.76406″N 11°49′13.45279″E / 59.2549344611°N 11.8204035528°E / 59.2549344611; 11.8204035528
29. ^ Tannsjøen Island ("Nr 54" on Norwegian map): 59°52′21.66852″N 11°54′59.30688″E / 59.8726857°N 11.9164741333°E / 59.8726857; 11.9164741333
30. ^ Linneholmene: 59°53′20.97974″N 12°1′59.95805″E / 59.8891610389°N 12.0333216806°E / 59.8891610389; 12.0333216806
31. ^ Jensøya: 59°53′35.76949″N 12°6′47.88010″E / 59.8932693028°N 12.113300028°E / 59.8932693028; 12.113300028
32. ^ Storøya: 60°0′55.9″N 12°23′42.5″E / 60.015528°N 12.395139°E / 60.015528; 12.395139
33. ^ Fallsjøholmen: 60°33′2.9″N 12°34′54.76″E / 60.550806°N 12.5818778°E / 60.550806; 12.5818778
34. ^ Kroksjøen's island: 60°44′02″N 12°23′43″E / 60.7338951°N 12.3953807°E / 60.7338951; 12.3953807
35. ^ Vonsjøen's island: 62°15′38″N 12°17′46″E / 62.26062499°N 12.29616058°E / 62.26062499; 12.29616058
36. ^ Skurdalssjøen's island: 63°21′28″N 12°05′10″E / 63.3576463°N 12.0859725°E / 63.3576463; 12.0859725
37. ^ Gihcijoka island: 67°39′55″N 16°34′11″E / 67.6653955°N 16.5696163°E / 67.6653955; 16.5696163
38. ^ Čoarvejávri's islands: largest:68°01′46″N 17°57′48″E / 68.0293635°N 17.9632280°E / 68.0293635; 17.9632280; middle:68°01′35″N 17°57′43″E / 68.0262611°N 17.9620527°E / 68.0262611; 17.9620527; southern:68°01′29″N 17°57′37″E / 68.0247914°N 17.9604023°E / 68.0247914; 17.9604023
39. ^ Krogh, Jan S.. "Lake Druksiai". http://geosite.jankrogh.com/lake_druksiai.htm. Retrieved 2006-12-10.  The international border is marked on the map.
40. ^ "World Lakes Database: LAKE DRUKSIAI". International lakes environment committee. http://www.ilec.or.jp/database/eur/eur-48.html. Retrieved 2006-12-10. "Number of main islands (name and area): Zamok (0.26 km²), Sosnovec (0.048 km²), Utovec (0.0088 km²) and 5 nameless islands." 
41. ^ "Bathymetric map of Lake Drūkšiai" (GIF). International lakes environment committee. http://www.ilec.or.jp/database/eur/eur48-01.gif. Retrieved 2006-12-10. ^{[dead link]} Sosnovec is named on this map.
42. ^ Coordinates of Lake Drūkšiai:55°37′N 26°38′E / 55.617°N 26.633°E / 55.617; 26.633
43. ^ Verified against Ordnance Survey of Ireland 6-inch map of the townland of Tober, County Donegal; surveyed 1905-05-05. Coordinates: 54°32′39″N 8°00′30″W / 54.5441°N 8.0084°W / 54.5441; -8.0084 Irish national grid reference system: G996663
44. ^ Office of the Geographer, Bureau of Intelligence and Research (1976-02-20) (PDF). International Boundary Study No. No. 154 – Djibouti – Ethiopia Boundary. United States Department of State. p. 8. http://www.law.fsu.edu/library/collection/LimitsinSeas/IBS154.pdf. "From Monument No. 53 on the south bank of Lake Abbe, the border crosses the lake from south to north continuing in a straight line for 30 kilometers. It cuts across the islet of hill 255 off Cape Aleilou." 
45. ^ "Map of Commune of Schengen" (PDF). Commune of Schengen. http://www.schengen.lu/fileadmin/Remerschen/files/Commune.pdf. Retrieved 2006-12-10. . Coordinates: 49°28′08″N 6°22′05″E / 49.46894°N 6.36812°E / 49.46894; 6.36812
46. ^ ^{a b} Дополнительное соглашение между Российской Федерацией и Китайской Народной Республикой о российско-китайской государственной границе на ее Восточной части от 14 октября 2004 года.
47. ^ The northern shore of Corocoro is on the open ocean, but it is not truly a sea island as the southern boundary is a freshwater channel. The island is claimed in its entirety by Venezuela. 8°31′01″N 60°04′59″W / 8.517°N 60.083°W / 8.517; -60.083
48. ^ Office of the Geographer, Bureau of Intelligence and Research (1985-04-15) (PDF). International Boundary Study No. 174: Brazil - Colombia boundary. United States Department of State. p. 8. http://www.law.fsu.edu/library/collection/LimitsinSeas/IBS174.pdf. "The final report allocated all river islands on the basis of the thalweg with the exception of San Jose Island on the Rio Negro which was split between Brazil (southern half) and Colombia."  Co-ordinates:1°13′42″N 66°51′17″W / 1.228401°N 66.854811°W / 1.228401; -66.854811
49. ^ Barros, Vicente (Coordinator) Impact Of Global Change On The Coastal Areas Of The Rio De La Plata: Sea Level Rise And Meteorological Effects. Page 7
50. ^ See map of Nawabganj District, map of Rajshahi District, and map of Daulatpur upazila of Kushtia District, all in Bangladesh.
51. ^ See map of Dilma upazila in Nilphamari District, Bangladesh.
52. ^ See map of Kurigram district, Bangladesh.
53. ^ Asiatic Society of Bangladesh. "Banglapedia: "Char"". http://banglapedia.search.com.bd/HT/C_0135.htm. Retrieved 2006-11-06. 
54. ^ Office of the Geographer, Bureau of Intelligence and Research (1964-11-23) (PDF). International Boundary Study No. 41: Greece - Turkey boundary. United States Department of State. p. 7. http://www.law.fsu.edu/library/collection/LimitsinSeas/IBS041.pdf. "Returning to the median of the Maritsa, [...] the boundary continues [...] to boundary marker No. 24 on the northern end of an island designated "Q". Thence, the boundary line extends a distance of 800.5 feet to marker No. 25 near the center, thence a distance of 1,804 feet to marker No. 26 on the southwestern extremity of island "Q"." 
55. ^ Map highlighting the islet in the Uutuanjoki from the Citizen's Map Site of Finland
56. ^ Islet in the Vadet near Tunnsjø: 64°38′40″N 13°42′38″E / 64.6444432°N 13.7105596°E / 64.6444432; 13.7105596
57. ^ Ramerini, Marco. "Dutch and Courlanders in Tobago: A history of the first settlements, 1628-1677". http://www.colonialvoyage.com/tobago.html. Retrieved 2007-10-01. 
58. ^ Wolff, Sir Henry Drummond (1855). The island empire, or, Scenes of the first exile of the Emperor Napoleon I: together with a narrative of his residence on the island of Elba, taken from local information, the papers of the British resident, and other authentic sources. Bosworth. pp. 304–322. http://books.google.com/books?id=5SJRAAAAYAAJ&pg=PA304. Retrieved 27 August 2011. 
59. ^ Frey, Linda; Frey, Marsha (1995). The treaties of the War of the Spanish Succession: an historical and critical dictionary. Greenwood Publishing Group. pp. 421–2. ISBN 9780313278846. http://books.google.com/books?id=wrJmCvFY6ocC&pg=PA421. Retrieved 27 August 2011. 
60. ^ Office of the Geographer (June 1969). "Chad-Nigeria boundary" (JPEG). United States Department of State. http://www.law.fsu.edu/library/collection/LimitsinSeas/maps/bs90.jpg. Retrieved 2006-12-06. 

External links

• Islands divided by International Borders