The Amazon River is the longest river in South America, flowing through Brazil and emptying into the Atlantic Ocean. Its main channel runs across northern South America, while its enormous drainage basin extends through several countries, including Peru, Colombia, Bolivia and Ecuador.
The river begins from headwaters in the Andes of Peru. Determining the exact source and length of the Amazon has been debated because different researchers choose different tributaries and measurement methods. Most modern geographical references place the Amazon among the two longest rivers on Earth, alongside the Nile, although rankings can vary with the definition used.
The Amazon carries more water than any other river. Its discharge is so large that freshwater can be detected far into the Atlantic. The river and its tributaries support extensive rainforest ecosystems, wetlands, fisheries and human communities. Portuguese explorers gave the river its European name, inspired by stories comparing Indigenous warriors to the Amazons of Greek mythology.