History of Paraguay its capital, and Río de la Plata, with headquarters in Buenos Aires. With this decision, Asunción lost control of the Río de la Plata estuary and became dependent on Buenos Aires for maritime shipping. In 1776, the crown created the Viceroyalty of Río de la Plata; Paraguay, which had been subordinate to Lima, now became a provincial outpost of Buenos Aires. Located at the periphery of the empire, Paraguay served as a buffer state. The Portuguese blocked Paraguayan territorial expansion in the north, native tribes blocked it – until their expulsion – in the south, and the Jesuits blocked it
Geography of Paraguay the river enters Paraguay, the Paraná River flows 800 km to its juncture with the Río Paraguay and then continues southward to the Río de la Plata Estuary at Buenos Aires, Argentina. In general, the Río Paraná is navigable by large ships only up to Encarnación, Paraguay but smaller boats may go somewhat farther. In summer months the river is deep enough to permit vessels with drafts of up to three meters to reach Salto del Guairá, but seasonal and other occasional conditions severely limit the river's navigational value. On the upper course, sudden floods may raise the water level