亚马逊河是世上流量、流域最大、支流最多的河流，也是世上最长的河流之一。上世纪，亚马逊河和尼罗河哪条是世上最长的河曾有过激烈争议。

The Amazon is the greatest river in the world by so many measures; the volume of water it carries to the sea (approximately 20% of all the freshwater discharge into the oceans)， the area of land that drains into it， and its length and width. It is one of the longest rivers in the world and， depending upon who you talk to， is anywhere between 6，259km/3，903mi and 6，712km/4，195mi long.

For the last century the length of the Amazon and the Nile Rivers have been in a tight battle for title of world's longest river. The exact length of the two rivers varies over time and reputable sources disagree as to their actual length. The Nile River in Africa is reported to be anywhere from at 5，499km/3，437mi to 6，690km/4，180mi long. But there is no question as to which of the two great rivers carry the greater volume of water - the Amazon.

At its widest point the Amazon can be 11km/6.8 mi wide during the dry season. The area covered by the Amazon River and its tributaries more than triples over the course of a year. In an average dry season 110，000 square km of land are water-covered， while in the wet season the flooded area

of the Amazon Basin rises to 350，000 square km. When the flood plains and the Amazon River Basin flood during the rainy season the Amazon River can be up to 40km/24.8 mi wide. Where the Amazon opens at its estuary the river is over 325km/202 mi wide!

Because the Amazon drains the entire Northern half of the South American continent (approx. 40% landmass)， including all the torrential tropical rains that deluge the rainforests， it carries an enormous amount of water. The mouth of the Amazon River， where it meets the sea， is so wide and deep that ocean-going ships have navigated its waters and traveled as far inland as two-thirds the way up the entire length of the river.