This is a list of the longest rivers on Earth
. It includes river systems over 1,000 kilometers.
Definition of length
The length of a river can be very hard to calculate. There are many factors, such as the source, the identification or the definition of the mouth, and the scale of measurementfor more on this, see coastline paradox
of the river length between source and mouth, that determine the precise meaning of "river length". As a result, the length measurements of many rivers are only approximations. In particular, there has long been disagreement as to whether the Nile
or the Amazon
is the world's longest river. The Nile has traditionally been considered longer, but in recent years some Brazilian and Peruvian studies have suggested that the Amazon is longer by measuring the river plus the adjacent Pará estuary and the longest connecting tidal canal.
For the purpose of determining maximum length a river's "true source" is considered to be the source of whichever tributary
is farthest from the mouth. This tributary may or may not have the same name as the main stem
river. For example, the source of the Mississippi River
is normally said to be Lake Itasca
in the U.S. state of Minnesota
, but the most distant source in the Mississippi system is that of the Jefferson......