The Putumayo River
Putumayo River, (in Brazil: Iĉa, a tributary of the Amazon River in east-central South America. Beginning in the Colombian Andes, it flows southeastward along the Colombia-Ecuador and Colombia-Peru borders, entering the Amazon in northwestern Brazil. The Putumayo is about 1,000 miles (1,600 km) long, and is navigable for most of its length.