The Putumayo River forms part of Colombia’s border with Ecuador, as well as most of the frontier with Peru. Known as the Putumayo in the former three nations, it is called the Içá when it crosses into Brazil. The Putumayo originates in the Andes Mountains east of the city of Pasto, Colombia. It empties into the Solimões (upper Amazon) near the municipality of Santo Antônio do Içá, Brazil.
Major tributaries include the Guamués River, San Miguel, Güeppí, Cumpuya, Algodón, Igara-Paraná, Yaguas, Cotuhé, and Paraná de Jacurapá rivers. The river flows through the Solimões-Japurá moist forests ecoregion.
The Putumayo is one of the last rivers in the Amazon that’s not regulated by a dam.
