What is the world's longest river by discharge volume?

The world's longest river by discharge volume is the Amazon River in South America. The Amazon River has the largest drainage basin in the world, with an area of approximately 7,050,000 square kilometers (2,722,000 square miles). The river's average discharge at its mouth is about 209,000 cubic meters per second (7,381,000 cubic feet per second), which is greater than the combined flow of the next seven largest rivers in the world. The Amazon River is approximately 6,400 kilometers (4,000 miles) long and flows through Brazil, Peru, Colombia, Ecuador, Venezuela, Bolivia, and Guyana.