colony · South America

Governorate of the Río de la Plata

1534 CE – 1617 CE · capital Asunción

The first Spanish governorate of the River Plate basin, which founded Buenos Aires and Asunción and opened the interior of southern South America.

Origins

In 1534 Charles V granted Pedro de Mendoza a governorate south of Pizarro's lands. Mendoza founded Buenos Aires in 1536, but hunger and attacks forced its abandonment in 1541. Juan de Salazar founded Asunción in 1537, upriver on the Paraguay river, and it became the capital of the governorate.

From Asunción, governors such as Domingo Martínez de Irala and Álvar Núñez Cabeza de Vaca ruled a frontier colony built on alliances with the Guaraní, many of whom were bound in encomiendas, and on mixed marriages that produced a large mestizo population. Expeditions sought a route to the silver of Peru. Juan de Garay founded Santa Fe in 1573 and refounded Buenos Aires in 1580. Hernandarias, the first Creole governor, promoted Jesuit missions.

In 1617 the crown split the vast governorate into the Governorate of Paraguay, based at Asunción, and the Governorate of Buenos Aires. Both later joined the Viceroyalty of the Río de la Plata created in 1776, and Asunción is remembered as the 'mother of cities' for the towns founded from it.

Governorate of the Río de la Plata was a colony of Spanish Empire1534 CE – 1617 CE
Governorate of the Río de la Plata was part of Viceroyalty of Peru1542 CE – 1617 CE
Governorate of Paraguay split from Governorate of the Río de la Plata1617 CE
Governorate of Buenos Aires split from Governorate of the Río de la Plata1617 CE

Cite this page

APA: The Epoch Institute. (2026). Governorate of the Río de la Plata. In The Epoch Institute States Register. https://the-epoch-institute.org/state/governorate-of-the-rio-de-la-plata
MLA: “Governorate of the Río de la Plata.” The Epoch Institute States Register, The Epoch Institute, 2026, https://the-epoch-institute.org/state/governorate-of-the-rio-de-la-plata. Accessed .
Chicago: The Epoch Institute. “Governorate of the Río de la Plata.” The Epoch Institute States Register. 2026. https://the-epoch-institute.org/state/governorate-of-the-rio-de-la-plata.
Harvard: The Epoch Institute (2026) ‘Governorate of the Río de la Plata’, The Epoch Institute States Register. Available at: https://the-epoch-institute.org/state/governorate-of-the-rio-de-la-plata (Accessed: ).

Last reviewed October 2026Random state ↻