The United Provinces of the Río de la Plata (Spanish: Provincias Unidas del Río de la Plata), earlier known as the United Provinces of South America (Spanish: Provincias Unidas de Sudamérica), was a name adopted in 1816 by the Congress of Tucumán for the region of South America that declared independence in 1816, with the Sovereign Congress taking place in 1813, during the Argentine War of Independence (1810–1818) that began with the May Revolution in May of 1810. It originally comprised rebellious territories of the former Spanish Viceroyalty of the Río de la Plata dependencies and had Buenos Aires as its capital.
The name Provincias del Río de la Plata (formally adopted during the Cortes of Cádiz to designate the Viceroyalty of the Río de la Plata) alludes to the Junta Provisional Gubernativa de las Provincias del Río de la Plata or Primera Junta. It is best known in Argentinean literature as Provincias Unidas del Río de la Plata ('United Provinces of the River Plate' i.e. 'river of silver'), this being the most common name (since 1811) in use for the country until the enactment of the 1826 Constitution. The Argentine National Anthem refers to the state as "the United Provinces of the South". The Constitution of Argentina recognises Provincias Unidas del Río de la Plata as one of the official names of the country, referred to as "Argentine Nation" (Nación Argentina) in modern legislation.
