The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about 6,300,000 km2 (2,400,000 sq mi), or about 35.5 percent of the South American continent. It is located in the countries of Bolivia, Brazil, Colombia, Ecuador, Guyana, Peru, Suriname, and Venezuela. Most of the basin is covered by the Amazon rainforest, also known as Amazonia. With a 5.5 million km2 (2.1 million sq mi) area of dense tropical forest, this is the largest rainforest in the world.