The Amazon River is approximately 6,400 kilometers long.
It rises in the Andes of Peru and flows eastward across South America before emptying into the Atlantic Ocean in Brazil. Its enormous drainage basin covers roughly 7 million square kilometers, making it the largest river basin in the world. The Amazon also carries more water than any other river, accounting for about one-fifth of global river discharge into the oceans.
The river’s exact length is debated because researchers differ over which distant Andean tributary should count as its true source and where the river officially begins at its mouth. For that reason, some estimates exceed 6,500 kilometers. The 6,400-kilometer figure remains a standard recognized estimate and is the fair quiz answer.
A common mix-up concerns the Amazon’s ranking by length. Depending on the measurement method, the Nile or Amazon may be described as the world’s longest river, but the Amazon is unquestionably the largest by water volume. In Brazil, the upper section is often called the Solimões River until it meets the Rio Negro near Manaus.