The largest river in the world is not as straight forward as one might think. In terms of length, the largest river is either the Amazon or the Nile. The reason this is not clear is because there are multiple, conflicting reports regarding each river’s length. The length of the Nile and Amazon differ by less than 200 miles and the longest depends upon where one identifies the river to end or begin. For instance, the mouth of the Amazon is so wide that there is debate over where the river ends and the ocean begins. There are similar debates regarding its source. According to the United States Geological Survey, the Nile is 4,132 miles in length while the Amazon River is 4,000 miles. A 2007 study by the Brazilian Institute of Geography and Statistics, however, indicates the length of the Amazon to be 4,250 miles.
Length aside, the Amazon River can be considered the largest river in most other aspects. The Amazon River has the largest drainage basin in the world, spanning 7,050,000 square kilometers (2,720,000 sq mi). Additionally, the Amazon River has the highest average rate of discharge, approximately 209,000 m3/s.
Also See The Largest