United Provinces of the Río de la Plata The United Provinces of South America ( ) was the original name of the state that emerged from the May Revolution and the early developments of the Argentine War of Independence . It comprised most of the former Viceroyalty of the Río de la Plata dependencies and had Buenos Aires as its capital . It is best known , in Spanish literature , as Provincias Unidas del Río de la Plata ( ) , this being the most common ( occasionally the official ) name in use for the country , until the enactment of the 1826 Constitution . Moreover , this is currently one of the official designations for Argentina , as stated in the Argentine Constitution , Article 35 . Description . The United Provinces of South America were neighboured to the south by the sparsely populated territories of the Pampas and Patagonia , home to the Mapuche , Ranquel and Puelche peoples . To the north , the Gran Chaco was populated by the Guaycuru nations . To the northwest , across the Upper Peru , lie the Spanish Viceroyalty of Perú . Across the Andes , to the west , it was the Spanish controlled Captaincy General of Chile . To the northeast , Colonial Brazil , a part of the Portuguese Empire which turned to be the United Kingdom of Portugal , Brazil and the Algarves in 1815 and the Empire of Brazil in 1821 . Government . The change from the Viceroyalty into the United Provinces was not merely a change of governors , but a revolutionary process that would replace the absolutist monarchy with a Republic . The main influences in this were the Enlightenment in Spain , promoting new ideas , and the Peninsular War that left Spain without a legitimate King after the Abdications of Bayonne . The concept of separation of powers gradually became a tool to prevent despotism . The new political situation generated great political conflict between the cities for two reasons . First , the " Vacatio Regis " removed the sovereignty from the King of Spain , but there was no clear view about who and how would be able to claim such sovereignty . Some people thought that it passed to other offices of the Spanish monarchy , while others held the notion of the retroversion of the sovereignty to the people : sovereignty returned to the people , who had now the right to self - governance . The vertical organization of the absolutist monarchy was compromised as well . Patriots thought that all cities , both in Spain and in the Americas , had the right to self - government , whereas Royalists recognized that power only to European Spain , holding that the Americas should stay subject to the new government that Spain would provide . The other source of conflict was the nature of the new governments , which declared themselves to be provisional during the King ' s absence but were making strong changes in the political organization . Unlike the First Republic of Venezuela , which declared independence early on , the United Provinces were faced with the inconsistency of acting like an independent state without actually having declared such independence . History . The United Provinces of the Río de la Plata were established through a lengthy process that started in May 1810 , when the citizens and militias of Buenos Aires , the capital city of the Viceroyalty of the Río de la Plata , ousted the Spanish Viceroy Baltasar Hidalgo de Cisneros in the May Revolution . Although there was not a formal declaration of independence at the time , and the government that emerged from the revolution declared loyalty to the deposed king Ferdinand VII , in fact it attempted to reorganise the social , political and economic structures of the Viceroyalty . As it faced immediate resistance in some quarters ( namely the Banda Oriental , under self - proclaimed Viceroy Javier de Elío , Córdoba under former Viceroy Santiago de Liniers , the local government of Asunción in Paraguay and - notably - the royalist forces from the Viceroyalty of Perú ) , the revolution soon turned to be a War of Independence . In the midst of the war of independence , during the entire 1810 - 1831 period there were serious conflicts among ever - changing factions regarding the organization of the state and the political aims of the revolutionary governments . These conflicts involved coup d ' états , mutinies , politically motivated trials , banishments and imprisonments and finally developed in an outright civil war . Initial revolutionary governments . Ever since the revolution , there were serious conflicts among diverging views regarding the political organization of the provinces . While some advocated a strong and executive central government with little accountability to the regional interests , a position at first favored by the " enlightened " revolutionary and independentist elements , others sought to integrate representatives from the provinces in a larger deliberative assembly . As the later position gained the upper hand , the Primera Junta grew to incorporate delegates from the provinces in 1811 . However , as it became evident that such an arrangement was not effective enough to lead the war efforts , a Triumvirate assumed the executive powers while the assembly retained some controlling functions . Liga Federal . The Liga Federal ( 1815 – 1820 ) or Liga de los Pueblos Libres ( League of the Free Peoples ) was an alliance of provinces in what is now Argentina and Uruguay , organised under democratic federalist ideals strongly advocated by its leader , José Gervasio Artigas . The government of the United Provinces of South America felt threatened by the growing appeal of the Liga Federal , so they did nothing to repel the incoming Portuguese invasion of Misiones Orientales and the Banda Oriental , the stronghold of Artigas . Brazilian General Carlos Frederico Lecor , thanks to their numerical and material superiority , defeated Artigas and his army and occupied Montevideo on , but the struggle continued for three long years in the countryside . Infuriated by the passivity of Buenos Aires , Artigas declared war on Buenos Aires while he was losing to the Portuguese . On , Federal League governors Francisco Ramírez of Entre Ríos and Estanislao López of Santa Fe , defeated a Supreme Directorship diminished army , ending the centralized government of the United Provinces , and established a federal agreement with Buenos Aires Province . Similarly , the Federal League effectively came to an end when its constituent provinces rejoined the United Provinces . Artigas , defeated by the Portuguese , had retreated to Entre Ríos . From there , he denounced the Treaty of Pilar and entered into conflict with his former ally governor Ramírez , who crushed the remnants of Artigas ' army . The former Protector of the Free Peoples exiled in Paraguay until his death . The Eastern Province was annexed by Portugal to its Brazilian dependences in 1821 . Break up of the Viceroyalty of the Río de la Plata . The result of the wars was the independence of the provinces : Bolivia . Five provinces would go on to become Bolivia Uruguay . The Eastern Province ( " Provincia Oriental " ) became independent as Uruguay . Brazil . Misiones Orientales was awarded to Brazil , following the outcome of the Cisplatine War . Argentina . Following a long civil war , the following Provinces joined to become the Argentine Republic : Falkland Islands . In the late 1820s , the United Provinces attempted to gain control over the Falkland Islands through the establishment of commercial interests in the islands . In 1820 , Colonel David Jewett while resting and repairing storm damage performed an act of possession of the islands stating he was acting on behalf of the Government of Buenos Aires . He made no mention of this in his report and it only became knowledge in Buenos Aires a year later as a foreign news story . Three years later , in 1823 , the United Provinces of the River Plate granted fishing and feral livestock rights to Jorge Pacheco . In 1824 , a short first expedition to the islands in association with Luis Vernet took place but failed shortly after landing due to supply problems and the harsh conditions . Pacheco disillusioned abandoned the enterprise leaving Vernet to proceed on his own . In 1826 , Vernet was aware of conflicting British claims to the islands and sought permission from the British consulate before departure . The departure to the islands was delayed by the Brazilian blockade and the expedition again failed to establish a permanent settlement . In 1828 , the United Provinces government granted Vernet all of East Falkland including all its resources , and exempted him from taxation if a colony could be established within three years . he also asked the United Provinces for naval assets to protect his colony but they were unable to provide them . The colony was eventually destroyed by conflict with the United States in the " Lexington " raid of 1832 . Later that year Major Esteban Mestivier was commissioned by the Buenos Aires government to set up a penal colony . He arrived at his destination on 15 November 1832 .