Paraná

The Parana river is Argentina's longest river. The Paraná River began on a plateau in southern Brazil and was named after a native word, para rehe onáva, which means as big as the sea. The Paraná River travels 3,032 miles (4,880 kilometers) before merging with the Paraguay and Uruguay rivers to form the Ro de la Plata. The Titetê and the Iguazu rivers are two of the most important tributaries of the Paraná River, with the Iguazu Falls, which has a remarkable total fall of around 275 cascades, making it the world's greatest waterfall.

The Paraná River, along with its tributaries, comprises a huge watershed that stretches throughout northern Argentina. The drainage basin of the river encompasses all of Paraguay, as well as considerable areas of Brazil, Argentina, Uruguay, and Bolivia. A substantial chunk of its navigable length connects inland cities in Argentina and Paraguay to the Atlantic. With the construction of Yacyretá Dam and Itaipu Dam, one of the world's largest, on its border, the Parana River has also made Paraguay the world's greatest exporter of electricity.

About 300 kinds of freshwater fish live in this Argentina's longest river. Nearly nine species of Potamotrygonidae freshwater river stingrays have been found in the Parana River, including the popular Motoro stingray and the smooth-back river stingray. The Aphyocharax paraguayensis population accounts for around half of the fish in the river. Otocinclus vittatus, Pseudohemiodon laticeps, and Otocinclus vestitus are only a few of the almost 80 species of loricariids. Other fish species found in the river include approximately 25 species of killifish and cichlids, South American lungfish, and three anostomidae.

Length: 3,032 miles (shared with Brazil and Paraguay)