List of proposed state mergers

This is a list of proposed state mergers, including both current and historical proposals originating from sovereign states or organizations. The entities listed below differ from separatist movements in that they would form as a merger or union of two or more existing states, territories, colonies or other regions, becoming either a federation, confederation or other type of unified sovereign state.

Historic

14th century

Proposed state	Components	Time period	Successful?	Notes
Angevin Union	Kingdom of Hungary Kingdom of Poland (1025–1385)	1370	Yes (1370–1382)	See Union of Hungary and Poland

15th century

Proposed state	Components	Time period	Successful?	Notes
Jagiellonian Union	Kingdom of Hungary Kingdom of Poland (1385–1569)	1440	Yes (1440–1444)	See Union of Hungary and Poland

16th century

Proposed state	Components	Time period	Successful?	Notes
Polish–Lithuanian Commonwealth	Kingdom of Poland (1385–1569) Grand Duchy of Lithuania	1569	Yes (1569–1795)	See Union of Lublin
Polish–Lithuanian–Muscovite Commonwealth	Polish–Lithuanian Commonwealth Tsardom of Russia	1574–1658	No

17th century

Proposed state	Components	Time period	Successful?	Notes
Polish–Lithuanian–Ruthenian Commonwealth	Polish–Lithuanian Commonwealth Cossack Hetmanate	1658–1659	No	Treaty of Hadiach

18th century

Proposed state	Components	Time period	Successful?	Notes
Kingdom of Great Britain	Kingdom of England  Kingdom of Scotland	1707	Yes	Though having been ruled since 1603 in Personal Union when James I succeeded both the English and Scottish crowns both countries remained separate sovereign nations states until 1706 when the Treaty of Union unified them into a single entity.
United States of America	Vermont Republic United States of America	1777–1791	Yes
United States of America	Connecticut  Delaware  Georgia  Maryland  Massachusetts  New Hampshire  New Jersey  New York  North Carolina  Pennsylvania  Rhode Island  South Carolina  Virginia	1786-1788	Yes (1788–1861)	United States Constitution is ratified by the Thirteen Original Colonies, replacing the Articles of Confederation and thereby forming a Federal government, ending the individual sovereignty of the US States.

19th century

Proposed state	Components	Time period	Successful?	Notes
United Kingdom of Great Britain and Ireland	Kingdom of Great Britain  Kingdom of Ireland	1800	Yes (1801–1922)	Most of Ireland left the union as the Irish Free State in 1922.
Gran Colombia	Viceroyalty of New Granada Venezuela Free Province of Guayaquil	1819–1830	Yes (1819–1830)	The old "Partido de Nicoya" currently encompasses most of the 21st-century Guanacaste Province
First Mexican Empire	Mexico El Salvador Honduras Nicaragua Guatemala Los Altos Disputed joining: Costa Rica	1821	Yes (1821–1823)	Central America was annexed into the First Mexican Empire. After the dissolution of the Empire only Chiapas choose to remain part of Mexico, the rest became the Federal Republic of Central America. Costa Rica in particular was split between inner factions in favor and against the annexation ending in a Civil War. The pro-Mexican provinces declared membership but was not recognized by the pro-independence provinces.
Federal Republic of Central America	El Salvador Honduras Nicaragua Guatemala Los Altos Costa Rica	1823	Yes (1823–1839)
Costa Rica	Costa Rica Nicoya	1824	Yes
Peru–Bolivian Confederation	Bolivia Peru	1829–1839	Yes (1836–1839)
United States of America	United States of America Republic of Texas	1845	Yes	Texas annexation
Kingdom of Italy	Kingdom of Sardinia Papal States Grand Duchy of Tuscany Duchy of Parma Duchy of Modena and Reggio Kingdom of the Two Sicilies Kingdom of Lombardy–Venetia (Part of Austrian Empire)	1848–1870	Yes	Although the Kingdom of Italy was proclaimed in 1861, the Italian Unification is generally considered to have been incomplete until after the integration of Venetia in 1866 and the capture of Rome in 1870. See Italian Unification and Expedition of the Thousand.
Federation of Central America	El Salvador Honduras Nicaragua	1852	Yes	Second attempt at unification that only lasted for less than a month.
Confederate States of America	South Carolina Mississippi Florida Alabama Georgia Louisiana Texas Virginia Arkansas North Carolina Tennessee	1861	Yes (1861-1865)	American Civil War
United Principalities	Wallachia Moldavia	1862	Yes	Becomes Kingdom of Romania in 1881.
Kingdom of Greece	Kingdom of Greece United States of the Ionian Islands	1864	Yes	Treaty of London (1864)
North German Confederation	Kingdom of Prussia  Kingdom of Saxony  Grand Duchy of Hesse  Mecklenburg-Schwerin  Grand Duchy of Mecklenburg-Strelitz  Grand Duchy of Oldenburg  Duchy of Saxe-Weimar-Eisenach  Duchy of Anhalt  Duchy of Brunswick  Duchy of Saxe-Altenburg  Saxe-Coburg-Gotha  Duchy of Saxe-Meiningen Various other small principalities and free cities	1866	Yes (1867–1871)	Following the Austro-Prussian War of 1866 and the annexation by Prussia of Austria's northern German ally states, Otto von Bismarck proposed to unify Prussia and its own German ally states into a single Federation. Consequently, the North German Constitution was adopted, with the provision that the southern German minor states could enter into the union when politically feasible.
Dominion of Canada	Province of Canada  New Brunswick  Nova Scotia	1867	Yes	Canadian Confederation
Antillean Confederation	Captaincy General of Cuba Captaincy General of Puerto Rico  Dominican Republic	1869–1870	No	Proposed by Ramón Emeterio Betances.
German Empire	North German Confederation Kingdom of Bavaria Kingdom of Württemberg Grand Duchy of Baden Grand Duchy of Hesse Alsace-Lorraine Austrian Empire	1871	Partial (1871–1918)	Unification of Germany (excluding Austria) after German victory over the French in the Franco-Prussian War. See also, the German Question regarding the competing ideas of "Greater Germany" and "Lesser Germany" (whether or not a united Germany should include the Austrian Empire). The matter was settled with the Austro-Prussian War in 1866, in which Prussia assumed leadership of the various minor German nation states.
Greater Republic of Central America	El Salvador Honduras Nicaragua Considered joining: Costa Rica  Guatemala	1895–1898	Yes (1896–1898)
United States of America	United States of America Republic of Hawaii	1898	Yes	United States annexation of the Territory of Hawaii

20th century

Proposed state	Components	Time period	Successful?	Notes
Australia	New South Wales  Queensland South Australia  Tasmania  Victoria  Western Australia Also invited: Fiji  New Zealand	1901	Yes	Federation of Australia
Balkan Socialist Federation	Principality of Albania  Kingdom of Bulgaria  Kingdom of Yugoslavia	1910–1916	No
Kingdom of Yugoslavia	Kingdom of Montenegro Kingdom of Serbia State of Slovenes, Croats and Serbs	1918	Yes (1918–1992)	Creation of Yugoslavia
Kingdom of Romania	Kingdom of Romania Moldavian Democratic Republic	1918	Yes (1918)	See Treaty of Bucharest
Kingdom of Romania	Kingdom of Romania Transylvania (Part of Hungary) Banat Republic Duchy of Bukovina	1918	Yes (1918–1947)	Unification of Greater Romania
Międzymorze	Belarusian People's Republic  Czechoslovak Republic  Estonia  Finland Hungarian People's Republic  Latvia  Lithuania  Polish Republic  Kingdom of Romania  Ukrainian People's Republic  Kingdom of Yugoslavia	November or December 1918	No	Also called "Intermarium". Suggested shortly after World War I to combat the influences of Germany and Russia.
Weimar Republic	Weimar Republic Republic of German-Austria	1918–1919	No	Following the disintegration of Austria-Hungary in the final days of World War I, the German-speaking territories of the Empire attempted to begin a process of integration into Weimar Germany. The Allies did not favor the idea, and forced the Austrian rump state to sign the Treaty of Saint Germain, which prohibited Austria from uniting with Germany.
Kingdom of Romania	Kingdom of Romania Kingdom of Hungary	1919	No	Federation between the Kingdom of Romania and the Kingdom of Hungary in personal union under the Romanian King, proposed by the Hungarian statesman István Bethlen.[1][2]
Ukrainian People's Republic	Ukrainian People's Republic West Ukrainian People's Republic	1919	Yes (1919)	Act Zluky
Soviet Union	Byelorussian SSR Russian SFSR Transcaucasian SFSR Ukrainian SSR	1922	Yes (1922–1991)	Treaty on the Creation of the USSR
Nazi Germany	Nazi Germany Federal State of Austria	1938	Yes (1938–1945)	Anschluss
Republic of Turkey	Republic of Turkey  Hatay State	1939	Yes	Hatay was a disputed territory between Syria and Turkey until 2004. Territory ceded from Syria to Turkey during the French Mandate of Syria, never formally recognized by Syria, but gave it up in 2004.
Polish-Czechoslovak confederation	Czechoslovak Republic  Polish Republic	1939–1948	No	Proposed by Władysław Sikorski.
Greek-Yugoslav confederation	Strictest definition:  Kingdom of Greece  Kingdom of Yugoslavia Loosest definition also includes:  Albanian Kingdom  Kingdom of Bulgaria  Kingdom of Romania	1942–1944	No
Socialist Federal Republic of Yugoslavia	Socialist Federal Republic of Yugoslavia People's Socialist Republic of Albania People's Republic of Bulgaria	1946–1948	No	Josip Broz Tito came extremely close to getting Albania into accepting integration into Yugoslavia, but relations cooled in 1948 over fears that Yugoslavia only intended to use Albania for raw materials, subsequently resulting in the expulsion of Yugoslav diplomats. Yugoslav/Bulgarian negotiations fell through when Moscow attempted to force both countries into accepting Soviet control over the merge, which caused Yugoslavia to withdraw from negotiations and precipitated the Tito–Stalin split.
India	India Junagadh	1947–1948	Yes	Annexation of Junagadh
India	India Princely states	1947–1950	Yes	Instrument of Accession
Pakistan	Pakistan Princely states	1947–1950	Yes	Instrument of Accession
India	India Hyderabad	1948	Yes	Annexation of Hyderabad
Canada	Canada Newfoundland	1949	Yes	Newfoundland Act
Federation of Rhodesia and Nyasaland	Nyasaland  Northern Rhodesia  Southern Rhodesia	1953	Yes (1953–1963)	A semi-independent state.
United Kingdom	United Kingdom Crown Colony of Malta	1956	No	See Maltese United Kingdom integration referendum, 1956.
North Borneo Federation	North Borneo Sarawak  Protectorate of Brunei	1956–1960	No	Sarawak and North Borneo (now known as Sabah) joined the Federation of Malaya several years later, a predecessor to modern Malaysia, while Brunei reformed into an independent monarchy.
United Arab States	United Arab Republic  Mutawakkilite Kingdom of Yemen	1958	Yes (1958–1961)	Loose confederation between the United Arab Republic and (North) Yemen.
West Indies Federation	British Barbados British Jamaica British Leeward Islands(except the Virgin Islands) British Trinidad and Tobago British Windward Islands Also invited: Crown Colony of the Bahama Islands British Guiana British Honduras British Virgin Islands	1958	Yes (1958–1962)	The expressed intention of the Federation was to create a political unit that would become independent from Britain as a single state, however, before that could happen, the Federation collapsed due to internal political conflicts.
United Arab Republic	Republic of Egypt Syrian Republic	1958	Yes (1958–1961)	A short-lived Pan-Arab state.
Arab Federation	Kingdom of Iraq  Jordan	1958	Yes (14 February – 2 August 1958)	An attempt to unify the two Hashemite kingdoms of Iraq and Jordan. While successful, the short-lived union was disestablished after a military coup deposed King Faisal II of Iraq.
Somali Republic	Somalia Somaliland	1960	Yes (1960–1991)	On June 26, 1960, the former British Somaliland protectorate briefly obtained independence as the State of Somaliland, with the Trust Territory of Somaliland following suit five days later.[3][4] The following day, on June 27, 1960, the newly convened Somaliland Legislative Assembly approved a bill that would formally allow for the union of the State of Somaliland with the Trust Territory of Somaliland on July 1, 1960.[5] Following the collapse of Barre's government in early 1991, local authorities, led by the SNM, unilaterally declared independence from Somalia on 18 May of the same year and reinstated the borders of the former short-lived independent State of Somaliland.
East African Federation	Kenya Tanganyika Uganda Zanzibar	1960–1964	No	Proposed political union between the four territories (one colony, two protectorates and one League of Nations mandated territory) under British rule in East Africa in the 1960s. Tanganyika proposed to delay its imminent independence in 1960 in order that the four territories might achieve independence together as one federation. In 1963 the leaders of all of the territories (some now independent) pledged to work towards a federation by 1964, but ultimately disputes over the nature of the federation and concerns about sharing power led to the collapse of effort to federate. Only Tanganyika and Zanzibar eventually united in 1964.
Malaysia	Malaya North Borneo Sarawak  Singapore Also invited:  Brunei	1963	Yes	Singapore was expelled from the federation on 9 August 1965 due to political conflict and power tension.
Tanzania	Tanganyika Zanzibar	1964	Yes
United Arab Emirates	Abu Dhabi Dubai  Sharjah  Ajman Umm al-Qaiwain Fujairah  Ras Al Khaimah Also invited: Bahrain Qatar	1971	Yes	Six independent emirates formed the United Arab Emirates in December 2, 1971. Ras Al Khaimah later joined the federation.
Arab Islamic Republic	Libya  Tunisia	1974	No	Proposed by Muammar Gaddafi.
India	India Sikkim	1975	Yes	After independence in 1947, joining the new Indian Union was rejected by popular vote. Sikkim grew closer to India over time, becoming a protectorate and later a suzerainty of India. With Indian pressure and support, Sikkim voted to join India in 1975.[6][7]
Vietnam	North Vietnam  South Vietnam	1976	Yes	Unified due to military conquest. See Reunification Day and the Fall of Saigon.
Federation of Arab Republics	Libya  Egypt  Syria Also invited:  Iraq  Sudan	1972–1977	Yes (1972–1977)	An attempt by Muammar Gaddafi to build a Pan-Arab state.
Senegambia Confederation	The Gambia  Senegal	1982–1989	Yes (1982–1989)	A loose confederation was formed, but ended due to the Gambia's lack of interest in integration.
Yemen	North Yemen  South Yemen	1990	Yes	Yemeni unification
Germany	East Germany  West Germany	1990	Yes	German reunification
Union of Sovereign States	Russian SFSR  Ukrainian SSR  Byelorussian SSR  Azerbaijan SSR  Kazakh SSR  Kirghiz SSR  Tajik SSR  Turkmen SSR  Uzbek SSR	1990–1991	No	An attempt by Mikhail Gorbachev to avert the collapse of the Soviet Union and reorganize the union into a new confederated entity.
FR Yugoslavia	SR Serbia  Montenegro  Bosnia and Herzegovina	1991	No	Zulfikarpašić–Karadžić agreement

21st century

Proposed state	Components	Time period	Successful?	Notes
Peru–Bolivian Confederation	Bolivia  Peru	2011	No	President Ollanta Humala of Peru proposed Bolivian president Evo Morales to reunite the countries in a confederation.[8][9] The Cabinets of the two countries have held joint meetings.[10]
Russia	Russia Crimea	2014	Yes	Crimea seceded from Ukraine and later conducted a referendum to join the Russian Federation and was later annexed by Russia. The referendum was controversial and most countries continue to recognize Crimea as part of Ukraine.
Unified Romania	Romania  Moldova	2018	No	Unification of Romania and Moldova has been proposed since 1991, supported by a minority according to polls, but Moldovan PM Pavel Filip ruled out reunification with Romania, despite growing calls from Moldovans for unification.[11] Unification was supported by the Romanian government. See also Greater Romania.

Current

Proposed state	Components	First proposed	Notes
United Ireland	Republic of Ireland Northern Ireland	1921	A United Ireland has been proposed since the Partition of Ireland (1921) and is supported by the main political parties in the Republic of Ireland, and by two of the four main parties in Northern Ireland. See also Unionism in Ireland and Nationalism in Ireland.
Unified Korea	North Korea  South Korea	1953	Korean reunification has been a goal for both Koreas since the 1953 armistice agreement. However, proposed strategies vary between the two Koreas, with both proposing the unification be done under one sociopolitical system while abandoning the other, similarly to German reunification.[12]
United China	People's Republic of China  Republic of China	1979	Unification of the mainland and the island is the stated goal of both governments.
United Republic of Cyprus	Republic of Cyprus  Turkish Republic of Northern Cyprus	1999	Proposed federal union between the two Cypriot states to end the Cyprus dispute.[13]
East African Federation	Burundi  Kenya  Rwanda  South Sudan  Tanzania  Uganda	2004	Proposed political union between the six member states of the East African Community.[14] Federation was proposed in 2004, but in 2016 it was decided that confederation would be the short-term goal. South Sudan is not as integrated as the other five members, having only gained independence from Sudan in 2011.[15]

See also

• Lists of active separatist movements
• List of irredentist claims or disputes
• Pan-nationalism
• Political union
• Irredentism

References