The Amazon lies wothin 160km of the Pacific Ocean and is 6,400 km long
20 to 25 percent of water that runs off the Earth's surface comes from the Amazon
The average discharge is 10 times that of the Mississippi River
It has 1,000 tributaires and the river's total drainage basin is nearly twice as large as the area drained by any other river in the world
Lying within 160 km of the Pacific Ocean at its westernmost source high in the Peruvian Andes, the Amazon flows almost 6,400 km across Brazil to its mouth in the Atlantic Ocean on the northeastern coast of Brazil. Its length is second only to that of the Nile. It is estimated that from 20 to 25 percent of all the water that runs off the Earths surface is carried to the Amazon.
The annual average discharge of 180,000 cubic m per second at its 240 km wide mouth is roughly 10 times that of North America's Mississippi River and about four times that of the Congo (Zaire) river in Africa, the world's second greatest river. The discharge is so great that it turns the oceans water from salty to brackish for more than 100 miles offshore. There are more than 1,000 known tributaries of the Amazon, rising in the Guiana Highlands, the Brazilian Highlands, and (principally) in the Andes. Seven of these are longer than 1,600 km, one, the Madeira, flowing northeastward from Bolivia, is more than 3,200 km long. Navigable throughout the year, the Amazon can accommodate large freighters as far inland as Manaus, 1,000 miles upriver from the Atlantic. The Amazon flows over a gently sloping terrain and is characterized by oxbow lakes, abandoned channels, and other marks of a meandering river. Floods, by depositing fertile silt as they recede, annually rejuvenate an area of some 65,000 square km, or nearly double that of The Netherlands, and the river's total drainage basin, about 7,047,000 square km, is nearly twice as large as the area drained by any other river in the world. The Amazon and its tributaries may be described as a vast sea of freshwater, supporting millions of fish, including catfish, electric eels and piranhas.