Which River Has the Most Tributaries?

The Amazon drainage basin covers approximately 7 million square kilometres — about 40% of South America and roughly the size of Australia. This vast catchment feeds the Amazon through over 1,100 named tributaries, of which 17 are each longer than 1,500 km (longer than the Rhine). The largest tributaries — the Rio Negro, Madeira, Japura, and Purus — would rank among the world largest rivers in their own right. The Amazon discharges about 209,000 cubic metres of water per second into the Atlantic Ocean, accounting for roughly 15-20% of all freshwater entering the world oceans. The meeting of the dark Rio Negro and the sandy-coloured Solimoes (Amazon) near Manaus creates the famous "Meeting of the Waters," where the two rivers run side by side for about 6 km before mixing, due to differences in temperature, speed, and density.