Measuring a river is surprisingly hard. Its true source can be disputed, its course shifts, and tributaries blur where one river ends and another begins. That is why you will see slightly different numbers in different atlases — and why two rivers, the Nile and the Amazon, are still locked in a contest for first place.
Here are the longest rivers in the world using the most widely accepted figures, followed by the facts behind the famous Nile-versus-Amazon debate.
The longest rivers, ranked
| River | Approx. length | Main countries | Outflow |
|---|---|---|---|
| Nile | 6,650 km (4,130 mi) | Uganda, Sudan, Egypt | Mediterranean Sea |
| Amazon | 6,400 km (3,980 mi) | Peru, Colombia, Brazil | Atlantic Ocean |
| Yangtze | 6,300 km (3,915 mi) | China | East China Sea |
| Mississippi–Missouri | 6,275 km (3,900 mi) | United States | Gulf of Mexico |
| Yenisei–Angara | 5,539 km (3,445 mi) | Mongolia, Russia | Arctic Ocean |
| Yellow River (Huang He) | 5,464 km (3,395 mi) | China | Bohai Sea |
The Nile vs. the Amazon
For most of modern history the Nile has been listed as the longest river on Earth. But several expeditions have argued that the Amazon is actually longer, depending on where its source is placed high in the Peruvian Andes and how its sprawling mouth is measured.
The honest answer is that the two are close enough — within a few tens of kilometres — that the result depends entirely on the measuring method. What is not disputed is that the Amazon is by far the largest river on Earth by volume: it discharges more water than the next seven largest rivers combined.
Rivers as lifelines
The great rivers have shaped human civilisation. The Nile made ancient Egypt possible; the Yangtze and Yellow River cradled Chinese civilisation; the Mississippi drains most of the central United States. Today these rivers still provide drinking water, irrigation, transport, hydroelectric power and habitat for an extraordinary range of wildlife.
Frequently asked questions
What is the longest river in the world?
The Nile is traditionally listed as the longest river at about 6,650 km, though some measurements put the Amazon slightly longer. The two are close enough that the answer depends on how each river’s source and mouth are defined.
Is the Amazon or the Nile longer?
By the most widely used figures the Nile is marginally longer, but several studies argue the Amazon is longer depending on its chosen source and mouth. The Amazon is undisputedly the largest river by water volume.
What is the longest river by volume of water?
The Amazon carries by far the most water of any river, discharging roughly 209,000 cubic metres per second into the Atlantic — more than the next several largest rivers combined.
What is the longest river in the United States?
The Missouri River is the longest single river in the United States, and combined with the Mississippi it forms the Mississippi–Missouri system, one of the longest river systems in the world at around 6,275 km.