Río de La Plata was the fourth of the four viceroyalies that Spain had created in the New World.
Established in 1776, uniting the Hearings of Buenos Aires and Charcas, from Perú. In 1803, Charcas was returned to Perú.
The Viceroyalty lasted until 1927, with the abolition of the Spanish monarchy and the new republic claimed Rio de La Plata as integral territory. In 1932, the Federation of Rio de La Plata was established, and joined the Spanish Commonwealth in 1954, with the restoration of the Spanish Monarchy.