The 10 longest rivers in Peru all eventually flow into the Amazon River -- either directly or via one of the Amazon’s many large tributaries.
The Amazon itself, of course, cuts across Peru and Brazil until it reaches the Atlantic Ocean. The vast Amazon Basin, meanwhile, covers about 40 percent of South America, including parts of Colombia and Ecuador, as can be seen in the map above.
The following 10 rivers in Peru are ordered according to their lengths within Peruvian territory. Some rivers, such as the Amazon (the second longest in the world, but not the longest in Peru), cross international borders, in which case the river’s total length may be much greater.
All river lengths given here are from Peru’s Instituto Geográfico Nacional (IGN).
At a length of 1,100 miles (1,771 km), the Ucayali River (Río Ucayali) is the longest river in Peru and a major tributary of the Amazon. The Ucayali begins in the Ucayali Region of Peru, a result of the confluence of the Río Urubamba and the Río Tambo.
The river runs directly north before reaching the major port city of Pucallpa. The Ucayali continues on a roughly northern course through the Peruvian jungle until it reaches the Pacaya-Samiria National Reserve (one of many protected natural areas in Peru and a popular reserve for spotting river dolphins, giant otters, and manatees), at which point it heads northeast to the port town of Nauta. The Ucayali and Río Marañón join near Nauta; this confluence is considered to mark the beginning of the Amazon River.
The Ucayali is one of the main river routes in Peru, both for cargo and passengers. Many river cruises begin in Pucallpa before heading down the Ucayali on the way to the Amazon River and Iquitos (from where you can head down the Amazon, through Brazil and on to the Atlantic Ocean).
The Marañón River is 879 miles long (1,414 km) and begins near the town of Rondos in the Huánuco Region of Peru -- but its true source lies further up the Lawriqucha and Nupe Rivers, which form to create the Marañón.
Since the 1700s, the Río Marañón has often been considered the source of the Amazon. Today, defining the source of the Amazon is very much open to debate; nonetheless, the Marañón is still frequently labeled a “main stem source” of the Amazon River due to its high annual discharge rates.
The Marañón begins as a relatively minor river, initially veering away from its ultimate destination -- the Amazon River -- while flowing through the Andes. The river heads in a roughly northerly direction through the central highlands, passing close to the towns of Celendín, Jaén (Cajamarca Region) and Bagua (Amazonas Region).
By this time, various smaller tributaries have turned the Marañón into a major river. After leaving the Andes, the Marañón cuts a path directly east through the jungle regions of Peru, during which time it is joined by a number of large tributaries, including the Pastaza, Huallaga and Tigre Rivers, greatly increasing its flow.
The Marañón then joins with the Ucayali River near Nauta, a confluence that marks the beginning of the Amazon River.
The course of the Marañón is marked by a number of well-known jungle gorges known as pongos. The most famous is the Pongo de Manseriche (pictured above), the final gorge before the Marañón enters the flat Amazon Basin. A particular 350-mile section of the Marañón has drawn comparisons with the Grand Canyon in the USA, earning the river the nickname of the "Grand Canyon of the Amazon." This section -- with its class III-IV rapids -- is a hotspot for rafting.
The Putumayo River begins in southwestern Colombia before flowing roughly southeast along part of the Ecuador-Colombia border, in total adding up to 857 miles (1,380) long. It then continues on its southeasterly course, delineating almost the entire Peru-Colombia border.
The Putumayo then enters Brazil near Tarapacá in the extreme southeast of Colombia. In Brazil, the Putumayo is known as the Içá. The river then flows directly into the Amazon River near the Brazilian town of Santo Antônio do Içá.
The Río Putumayo is a major transport route through the western Amazon Basin to the Amazon River. It is navigable throughout the year, from Puerto Asis in Colombia all the way to the Amazon and on to the Atlantic Ocean.
The Río Yavarí (also Javary, Javari), like the Putumayo, is a boundary-defining river at 736 miles (1,184 km) long. The Yavarí begins in the eastern jungles of Peru, the result of the confluence of the Río Jaquirana (Peru) and the Río Batã (Brazil). It then flows northeast (and roughly parallel to the Río Ucayali), forming the Peru-Brazil border for approximately 500 miles.
The Yavarí enters the Amazon River downstream from Iquitos, near a small Brazilian town called Benjamin Constant. There are no major ports along the Yavarí, but there are small villages and some private wildlife-spotting stations dotted along its course.
Measuring 707 miles (1,138 km) the Huallaga River (Río Huallaga) is the fifth longest river in Peru and the longest river in Peru that doesn’t flow directly into the Amazon.
The Huallaga begins its largely northerly course in the Huánuco Region in the central highlands of Peru. It flows past the city of Tingo Maria and further north into the San Martín Region, passing Tocache, Juanjuí and Bellvista. Near Tarapoto, the Huallaga cuts east to Chazuta before heading north to the port town of Yurimaguas. North of Yurimaguas, and on the western fringe of the Pacaya-Samiria National Reserve, the Huallaga enters the Marañón River, which then enters the Amazon.
The Huallaga is a generally perilous river and not suitable for navigation, apart from the section from Yurimaguas to the Marañón. The Upper Huallaga Valley (the section from Tocache south to the river’s source) is the world's single largest source of cocoa; it is also the main drug-producing/trafficking region of Peru and a hub for remnants of the Shining Path.
The Urubamba River, measuring 536 miles (862 km) long, is most famous for running through the Urubamba Valley, otherwise known as the Sacred Valley of the Incas.
The Urubamba begins life under a different name: Río Vilcanota (or Willkanuta -- "House of the Sun" -- in the native Aymara language). It flows north and passes to the east of the city of Cusco, running by Pisac and on through the Sacred Valley. Upon reaching the town of Urubamba to the northwest of Cusco, the river takes on its second name.
The newly christened Río Urubamba flows northwest to Ollantaytambo before snaking through Aguas Calientes and around the Historic Sanctuary of Machu Picchu. The river then cuts north, where it runs through the Pongo de Mainique, a two-mile-long whitewater canyon, before pushing further north to join the Río Tambo, the two rivers converging to form the Río Ucayali.
The Mantaro River begins in the central highlands near Cerro de Pasco and travels for 450 miles (724 km). Here, various smaller streams flow into Lake Junín, from which flows the main body of the Río Mantaro. The river flows southeast through the fertile and culturally important Mantaro Valley, passing through the cities of Jauja, Concepción and on to Huancayo.
The Mantaro then cuts a large “S” as it snakes its way east to join the Río Apurímac, where the two rivers form the Río Ene. The Ene then becomes the short Río Tambo, which in turn joins the Río Ucayali, which converges with the Marañón to form the Amazon River.
If that sounds like quite a journey, it may come as no surprise that recent research has shown that the Mantaro River might be the true longest upstream source feeding into the Amazon Basin.
The precise length of the Amazon River (Río Amazonas) is subject to much debate, but it is generally considered the second longest river in the world (after the Nile) with a total length of at least 4,000 miles (6,400 km).
In Peruvian territory, however, the Amazon only ranks at number eight in the list of the country’s longest rivers -- but all of Peru’s longest rivers eventually end up in the Amazon.
The Amazon River begins, at least in name, near the Peruvian jungle town of Nauta at the confluence of the Río Ucayali and Río Marañón. The most distant source of the Amazon River, however, is believed to be a glacial stream flowing from Nevado Mismi, a mountain in the Arequipa Region of Peru (the meltwaters of which feed the Apurímac River).
After its creation at the confluence of the Ucayali and Marañón, the Amazon River flows north to Iquitos (see satellite photo above; the massive brown swathe below the city is the Amazon River, the smaller river is the Nanay River).
The Amazon then heads east (where it is joined by the Río Napo), forming part of the Peru-Colombia border before entering Brazil. In Brazil, the Río Amazonas is known as the Río Solimões until its confluence with the Rio Negro, after which it is called Amazonas.
The Apurímac River (Río Apurímac), 429 miles (690 km), has a strong claim when it comes to defining the true source of the Amazon River. Of the 10 longest rivers in Peru, the Apurímac has the most southerly source -- and therefore the furthest from the Amazon River itself.
The Río Apurímac begins in the mountains of the Arequipa Region of Peru, fed from glacial meltwaters from Nevado Mismi, a mountain that rises to about 18,360 feet. From Nevado Mismi, the Apurímac flows north towards Cusco but heads northwest in a series of deep, narrow gorges before reaching the former Inca capital.
It then passes near the Choquequirao archaeological site and continues in a roughly northwesterly direction until converging with the Río Mantaro. The two rivers join and become the Río Ene, which in turn becomes the Río Tambo; the Tambo then joins the Río Ucayali, which later converges with the Marañón to form the Amazon River.
The Napo River begins in Ecuador and runs almost parallel to the Putumayo River (running slightly further north) for 414 miles (667 km). The river has its source near the Antisana stratovolcano in Ecuador, after which it flows due east toward the extreme north of Peru.
Having entered Peru, the Napo cuts a southeasterly path through the dense jungles of northern Peru on its way toward Iquitos. To the northeast of Iquitos, the Napo flows into the Amazon River, becoming the last major tributary of the Amazon before it flows into Brazilian territory.
The Río Napo is navigable from the Amazon at least as far as Coca in northeastern Ecuador. Adventurous travelers can take riverboats from Coca all the way to Iquitos.