The Amazon River is the world’s largest and most important river system. It has a drainage basin that covers about 7,050,000 km² (2,720,000 mi²). This makes it larger than any other river basin in the world. The total length of this river is approximately 6500 kilometers long with an average flow rate of around 190 million gallons per second. Within this are many tributaries that are also significant, such as the Paraná and Ucayali rivers, which combine to form the Marañón River system.
The Amazon River is the world’s longest river and also its largest in terms of water volume. The Amazon accounts for approximately 20% of the world’s total river flow.
It flows through Brazil, Peru, Ecuador, Colombia, Venezuela, Bolivia, Guyana, Suriname, and French Guiana before draining into the Atlantic Ocean.
The Amazon is the world’s second-longest river after the Nile River in Africa, and it has the largest drainage basin (area of land from which all water drains into the ocean) in the world, approximately 7 million square kilometers (2.7 million sq mi), or roughly 40 percent of South America.
The Amazon, particularly the southern parts of the river where it is known as Solimoes, has a very large number of tributaries. If you consider all its tributaries and streams up to 1 km in length, it will be about 16,000 kilometers long – well over halfway around the world – compared with Nile’s 6,853 km. It is fair to say that the Amazon is much longer than any river in Europe, Asia, or North America.
The width of the Amazon at its widest part ranges from 2.4 kilometers (1.5 miles) near Óbidos, Pará to 170 kilometers (106 mi) upstream from the river’s mouth at the Atlantic Ocean.
The Amazon River is actually a collection of whitewater, which includes several smaller rivers flowing into it. These are not large when compared with other major rivers in South America, but when all these small rivers are combined they make the mouth of the Amazon much wider than would be seen from satellite images.
The mouth of the Amazon is ~200 kilometers (120 mi) wide, and the width of the river at this point is more than 3.7 km (2.3 mi).
The Amazon’s mouth, on the Atlantic Ocean, is not only very large and important to shipping and transport through Brazil and Peru, but it also has a very strong outflow of freshwater. This outflow is called the Amazon’s large mouth because it has a stronger flow than any of the rivers that feed into it.
The Amazon is the only river that has such a strong flow into an ocean. For comparison, the Mississippi River in North America is not much longer than the Nile, but it has a much smaller drainage basin and its outflow water is much saltier than fresh because it picks up salts from all the country through which it passes.
The Amazon’s outflow of freshwater into the Atlantic Ocean is a major factor in influencing climate across all of South America.