The Madeira River ( ) is a major waterway in South America. It is estimated to be in length, while the Madeira-Mamoré is estimated near or 3380 km in length depending on the measuring party and their methods. The Madeira is the biggest tributary of the Amazon, accounting for about 15% of the water in the basin. A map from Emanuel Bowen in 1747, held by the David Rumsey Map Collection, refers to the Madeira by the pre-colonial, indigenous name Cuyari: