The eastern portions of Peru includes the Amazon Basin or selva baja, a region that is larger in the north than in the south. Representing roughly 60% of Peru's national territory, this area includes the Amazon, Marañón, Huallaga and Ucayali Rivers. It is a vast tropical forest with countless rivers and streams. Rainfall varies from 2,000 to 4,000 mm (78.7 to 157.5 in) per year.
Almost 60% of the country's area is located within this region, (70,000,000 hectares / 172,973,767 acres or 700,000 km2/270,272 sq mi) giving Peru the fourth largest area of tropical forest in the world after Brazil, Congo and Indonesia.