Оңтүстік Америкадағы Рио-де-ла-Плата өзені және сағасы

River or estuary in South America

If considered a river, it is the widest in the world, with a maximum width of

The river is about long and widens from about at its source to about at its mouth. It forms part of the border between Argentina and Uruguay. The name Río de la Plata is also used to refer to the populations along the estuary, especially the main port cities of Buenos Aires and Montevideo, where Rioplatense Spanish is spoken and tango culture developed. The coasts of the river are the most densely populated areas of Uruguay and Argentina. Though it is generally spoken of as a river, the Río de la Plata is considered by some geographers to be a large bay or marginal sea of the Atlantic Ocean. The shoal is located approximately between Montevideo and Punta Piedras (the northwest end of Samborombón Bay). The inner fluvial zone is about long and up to wide, with a depth which varies from about ; the depth of the outer estuary zone increases from .

The Río de la Plata behaves as an estuary in which freshwater and seawater mix. The freshwater comes principally from the Paraná River (one of the world's longest rivers and La Plata's main tributary) as well as from the Uruguay River and other smaller streams. Currents in the Río de la Plata are dominated by tides reaching to its sources and beyond, into the Uruguay and Paraná rivers. is the hydrographical area that drains to the Río de la Plata. It includes areas of southeastern Bolivia, southern and central Brazil, the entire country of Paraguay, most of Uruguay, and northern Argentina. Making up about one fourth of the continent's surface, it is the second largest drainage basin in South America (after the Amazon basin) and one of the largest in the world.

The Río de la Plata was first explored by the Portuguese in 1512–13. The Spanish first explored it in 1516, when the navigator Juan Díaz de Solís traversed it during his search for a passage between the Atlantic and the Pacific Oceans, calling it the Mar Dulce, or "freshwater sea." Explorer Sebastian Cabot made a detailed study of the river and its tributaries and gave it its modern name. He explored the Paraná and Uruguay rivers between 1526 and 1529, ascending the Paraná as far as the present day city of Asunción, and also explored up the Paraguay River. Cabot acquired silver trinkets trading with the Guaraní near today's Asunción, and these objects (together with legends of a "Sierra de la Plata" in the South American interior brought back by earlier explorers) inspired him to rename the river "Río de la Plata" ("River of Silver"). Buenos Aires was re founded by Juan de Garay on 11 June 1580. Under the Bourbon monarchy, the governorate was elevated to the Viceroyalty of the Río de la Plata in 1776. This occurred as a result of the Bourbon Reforms, which attempted to restore the decaying wealth of the Spanish Crown. The reforms elevated the status of trade along the Río de la Plata and expanded what constituted "legal" trade so that the Crown could tax trade which had previously been "contraband." However, the plan did not go as intended. Although trade along the Río de la Plata flourished, very little silver was actually remitted to the Crown. Then, Spanish war with Britain and the simultaneous eruption of revolts in the mining regions of Peru led to a shortage of silver, putting strain on the merchant class of Buenos Aires. This caused a schism between merchants who wanted to try to continue reviving the Spanish Empire through silver trade and those who wanted to move on from silver and prioritize agricultural exports, ultimately tearing at the fabric of the Río de la Plata region's relationship with the Spanish Empire. In 1806 and 1807 the river was the scene of an important British invasion that aimed to occupy the area and was defeated by the local garrison and population.

Conflict in the region intensified after the independence of the former Spanish and Portuguese colonies in the first quarter of the 19th century. Interests in the territories and the navigation rights over the Platine region played a major role in many armed conflicts throughout the century, including the Argentine civil wars, the Cisplatine and Platine wars, and the Paraguayan War.

In the first major naval engagement of the war, an Argentine squadron left port in the early hours of February 9 to challenge the blockade. The battle was inconclusive, with the Argentine fleet breaking contact and the Brazilian admiral failing to give chase.

In July 29, a Brazilian fleet led by the English admiral James Norton engaged Brown's fleet near Ensenada. Norton split his force, catching the Argentine line between two fires and causing significant casualties. William Brown's flagship, the frigate 25 de Mayo, sank after the battle as a result of the damage received.

In 8–9 February, an Argentine fleet led by Brown engaged the Third Division of the Imperial Navy on the Uruguay River, inflicting heavy casualties against a disorganized Brazilian squadron. The Argentines routed the Third Division, capturing or destroying fifteen Brazilian vessels whilst losing none and frustrating the Brazilian attempt to control the Uruguay river.

Near the coast of Ensenada in April 7, four Argentine vessels led by Brown slipped out of port in an unsuccessful attempt to surprise a large Brazilian fleet under the command of Norton. Two brigs were sunk, and a schooner was heavily damaged, resulting in a decisive Brazilian victory that ensured the Imperial blockade of the Río de la Plata until the Preliminary Peace Convention of 1828. The blockade caused serious problems to the export oriented economy of Buenos Aires but indirectly contributed to rural provinces such as Córdoba, allowing producers to sell native products to Buenos Aires at an increased price.

In the first naval battle of the Second World War the German pocket battleship Admiral Graf Spee was engaged by the Royal Navy (RN) cruisers and , and the Royal New Zealand Navy cruiser HMNZS Achilles, off the estuary of the River Plate in December 1939. The German ship retired up the estuary with a crippled fuel system and put into port at Montevideo. A few days later, rather than fight when believing himself outgunned, her captain scuttled her in the estuary. This engagement was part of the early Battle of the Atlantic.

The historical English name "River Plate" uses an obsolete sense of the word "plate", which was used extensively as a term for "silver" or "gold" from the 12th century onwards, especially in Early Modern English. The estuary has been known as the River Plate or Plate River in English since at least the time of Francis Drake. This English version of the name served as an inspiration for one of Argentina's most important football clubs, Club Atlético River Plate. A more literal translation of the name is "Silver River", though this is virtually never used in practice.

The Río de la Plata is a habitat for the loggerhead sea turtle, green sea turtle, leatherback sea turtle, the rare La Plata dolphin, and many species of fish.