Río de la Plata Basin in the context of "The Americas"

The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America. When viewed as a single continent, the Americas are the 2nd largest continent by area after Asia and the 3rd largest continent by population. The Americas make up most of the land in Earth's Western Hemisphere and constitute the New World.

Along with their associated islands, the Americas cover 8% of Earth's total surface area and 28.4% of its land area. The topography is dominated by the American Cordillera, a long chain of mountains that runs the length of the west coast. The flatter eastern side of the Americas is dominated by large river basins, such as the Amazon, St. Lawrence River–Great Lakes, Mississippi, and La Plata basins. Since the Americas extend 14,000 km (8,700 mi) from north to south, the climate and ecology vary widely, from the arctic tundra of Northern Canada, Greenland, and Alaska, to the tropical rainforests in Central America and South America.

The Viceroyalty of the Río de la Plata or Viceroyalty of Buenos Aires (Spanish: Virreinato del Río de la Plata or Virreinato de Buenos Aires or Spanish: Virreinato de las Provincias del Río de la Plata) meaning "River of the Silver", also called the "Viceroyalty of River Plate" in some scholarly writings, in southern South America, was the last to be organized and also the shortest-lived viceroyalty of the Spanish Empire in the Americas. The name "Provincias del Río de la Plata" was formally adopted in 1810 during the Cortes of Cádiz to designate the Viceroyalty of the Río de la Plata.

The Viceroyalty was established in 1776 from several former Viceroyalty of Perú dependencies that mainly extended over the Río de la Plata Basin, roughly the present-day territories of Argentina, northern Chile, Bolivia, Paraguay and Uruguay, extending inland from the Atlantic Coast. The colony of Spanish Guinea (present-day Equatorial Guinea) also depended administratively on the Viceroyalty of Rio de la Plata. Buenos Aires, located on the western shore of the Río de la Plata estuary flowing into the Atlantic Ocean, opposite the Portuguese outpost of Colonia del Sacramento, was chosen as the capital. Usually considered one of the late Bourbon Reforms, the organization of this viceroyalty was motivated on both commercial grounds (Buenos Aires was by then a major spot for illegal trade), as well as on security concerns brought about by the growing interest of competing foreign powers in the area. The Spanish Crown wanted to protect its territory against Great Britain and the Kingdom of Portugal.

Montevideo (/ˌmɒntɪvɪˈdeɪoʊ/, US also /-ˈvɪdioʊ/; Spanish: [monteβiˈðeo] ) is the capital and largest city of Uruguay. According to the 2023 census, the city proper has a population of 1,302,954 (about 37.2% of the country's total population) in an area of 201 square kilometers (78 sq mi). Montevideo is situated on the southern coast of the country, on the northeastern bank of the Río de la Plata.

A Portuguese garrison was established in the place where today is the city of Montevideo in November 1723. The Portuguese garrison was expelled in February 1724 by a Spanish soldier, Bruno Mauricio de Zabala, as a strategic move amidst the Spanish-Portuguese dispute over the platine region. There is no official document establishing the foundation of the city, but the "Diario" of Bruno Mauricio de Zabala officially mentions the date of 24 December 1726 as the foundation, corroborated by presential witnesses. The complete independence from Buenos Aires as a real city was not reached until 1 January 1730. It was also under brief British rule in 1807, but eventually the city was retaken by Spanish criollos who defeated the British invasions of the River Plate. Montevideo is the seat of the administrative headquarters of Mercosur and ALADI, Latin America's leading trade blocs, a position that entailed comparisons to the role of Brussels in Europe.

Asunción (English: /ɑːˌsuːnsiˈoʊn, ˌɑːsuːnˈsjoʊn/, Spanish: [asunˈsjon]; Guarani: "Paraguay") is the capital and the largest city of Paraguay. The city stands on the eastern bank of the Paraguay River, almost at the confluence of this river with the Pilcomayo River. The Paraguay River and the Bay of Asunción in the northwest separate the city from the Occidental Region of Paraguay and from Argentina in the south part of the city. The rest of the city is surrounded by the Central Department.

Asunción is one of the oldest cities in South America and the longest continually inhabited area in the Río de la Plata Basin; for this reason it is known as "the Mother of Cities". From Asunción, Spanish colonial expeditions departed to found other cities, including the second foundation of Buenos Aires, that of other important cities such as Villarrica, Corrientes, Santa Fe, Córdoba, Santa Cruz de la Sierra and 65 more. According to the 2022 Paraguayan Census, Asunción has 462,241 inhabitants, while its metropolitan area (known as Greater Asunción) exceeds 2.3 million inhabitants, making it the most densely populated area in Paraguay, and also the most productive as it concentrates 70% of the National GDP. Asunción is the third most populated "jurisdiction" or "political division" in the country, surpassed by the Central and Alto Paraná departments.

Rioplatense Spanish (/ˌriːoʊpləˈtɛnseɪ/ REE-oh-plə-TEN-say, Spanish: [ˌrioplaˈtense]), also known as Rioplatense Castilian or River Plate Spanish, is a variety of Spanish originating in and around the Río de la Plata Basin, and now spoken throughout most of Argentina and Uruguay. This dialect is widely recognized throughout the Hispanosphere due to its strong influence from Italian languages, a result of significant historical Italian immigration to the region. As a consequence, it has incorporated numerous Italian loanwords—giving rise to the lunfardo argot—and is spoken with an intonation similar to that of the Neapolitan language from Southern Italy.

It is the most prominent dialect to employ voseo (the use of vos in place of the pronoun tú, along with special accompanying conjugations) in both speech and writing. Many features of Rioplatense Spanish are also shared with the varieties spoken in south and eastern Bolivia, as well as in Paraguay, particularly in regions bordering Argentina. It also strongly influences the fronteiriço, a pidgin spoken in Uruguay's border regions with Brazil, as a result of continuous interaction between the communities of both nations.