What is the world's largest river by water volume?

The world's largest river by water volume is the Amazon River. It has the greatest average discharge of any river on Earth, sending more water into the Atlantic Ocean than any other river system.

The Amazon drains a vast basin covering about 7 million square kilometers across much of South America. Its average discharge near the mouth is roughly 209,000 cubic meters per second, although the amount changes substantially between wet and dry seasons. The river system accounts for approximately one-fifth of the freshwater carried by all rivers to the world's oceans.

The Amazon begins in the Andes of Peru and flows eastward through Brazil before reaching the Atlantic. Major tributaries include the Rio Negro, Madeira, Tapajós, Xingu, Marañón and Ucayali. Near its mouth, the river becomes so broad that opposite shores can be difficult to see.

A frequent mix-up concerns length rather than volume. The Nile is often described as the longest river, although measurements involving the Amazon's most distant headwaters remain debated. By water discharge, however, the Amazon is the clear standard answer.