Rivers of the Amazon Basin
The most distant headwaters of the Amazon’s largest rivers lie between approximately 2,500 and 6,800 km from the river mouth. Much of the debate about which tributary reaches farthest centers on which stream within the Ucayali Basin is most distant from the mouth, and on the exact location of the mouth itself.
The most distant headwaters of the Amazon River are located almost 6,100 kilometers from the Atlantic after considering the distances following the winding course of the great canals and tributaries. Map: Wildlife Conservation Society 2024.
In recent years several expeditions have attempted to locate the headwater of the Amazon River. The aim has been to determine the exact origin, to define if the great Amazon is longer than the Nile. Using global positioning systems (GPS) and with an accuracy of a few dozen meters, it was possible to locate it in the department of Arequipa, south of Cusco, in the Ucayali basin.
The problem, however, is that expedition members did not re-measure distances to the Atlantic Ocean. Instead, they appended their new findings to downstream figures already published but not necessarily verified independently. There are plenty of estimates of the length of the Amazon River, ranging from 6,000 to 7,800 km. If the higher estimates are accepted, then one can conclude that the Amazon is indeed longer than the Nile.
Department – Country: Amazonas – Brazil Main Basin – Sub Basin: Madeira – Madeira Main Stem Photographer: Luiz Claudio Marigo
The best estimate we have is that the Amazon River is approximately 6,500–6,800 km long if the mouth is located near Balique, just east of 50° W. The length of the Nile is usually stated to be 6,650 km. Undoubtedly, the “longest river” debate will continue until both rivers are measured in the same way, at about the same time, preferably by the same team of researchers.
Amazon tributaries
South Americans divide the Amazon River into four main stretches, with two stretches named “Amazonas”.
The beginning upriver in Peru is the Ucayali, followed downstream by the Amazonas in Peru and Colombia. Further downstream, after entering Brazil, the Amazon River is called the Solimões until its confluence with the Negro, where it is again called the Amazonas. The main headwater rivers of the Ucayali Basin, from upstream to downstream, are the Apurímac, the Ene, and the Tambo.
The Amazon Basin is the only river basin in the world that has three tributaries longer than 3,000 km (the Purus, the Juruá and the Madeira). The Madeira River, at 3,352 km, is the longest, but it is still second to the Missouri River, which at 3,726 km is the longest tributary in the world. The Purús and the Juruá, along with the Ucayali, are the longest meandering rivers in the Amazon, all southern tributaries of the Basin.
This serpentine trio flows across an enormous alluvial plain where the flat, low-gradient terrain offers little resistance to the flow, allowing these rivers to develop extensive meanders across their broad floodplains. The length of the Purús, for example, is more than twice the straight-line distance from its mouth to its headwaters.
RIVER TYPES
Whitewater Rivers
Blackwater Rivers
Clearwater Rivers