The Paraguay River is a major river in south central South America. It goes through Brazil, Bolivia, Paraguay, and Argentina. It is about 2,621 kilometres (1,629 miles) long.[2] It starts in the Brazilian state of Mato Grosso. It ends when it joins the Paraná River north of Corrientes. The biggest city on the river is Asunción, the capital city of Paraguay, which is located at its meeting with the Putumayo River.