Ucayali River in the context of "Arequipa region"

The Amazon River (US: /ˈæməzɒn/; Portuguese: rio Amazonas, Spanish: río Amazonas) in South America is the largest river by discharge volume of water in the world, and the longest or second-longest river system in the world, a title which is disputed with the Nile.

The headwaters of the Apurímac River on Nevado Mismi had been considered, for nearly a century, the Amazon basin's most distant source until a 2014 study found it to be the headwaters of the Mantaro River on the Cordillera Rumi Cruz in Peru. The Mantaro and Apurímac rivers join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, forming what countries other than Brazil consider to be the main stem of the Amazon. Brazilians call this section the Solimões River above its confluence with the Rio Negro forming what Brazilians call the Amazon at the Meeting of Waters (Portuguese: Encontro das Águas) at Manaus, the largest city on the river.

The Apurímac River (Quechua: Apurimaq mayu IPA: [ˈapʊ ˈɾɪmaχ ˈmajʊ]; Spanish: río Apurímac, IPA: [ˈri.o apuˈɾimak]; from Quechua apu 'chief' and rimaq 'the one who speaks, oracle', thus 'the chief oracle') rises from glacial meltwater of the ridge of the Mismi, a 5,597-metre-high (18,363 ft) mountain in the Arequipa Province in the south-western mountain ranges of Peru, 10 km (6.2 mi) from the village Caylloma, and less than 160 km (99 mi) from the Pacific coast. It flows generally northwest past Cusco in narrow gorges with depths of up to 3,000 m (9,800 ft), almost twice as deep as the Grand Canyon, its course interrupted by falls and rapids. Of the six attempts to travel the full length of the Apurímac so far, only two have been successful.

After 730 kilometres (450 mi), the Apurímac joins the Mantaro River and becomes the Ene River, 440 m (1,440 ft) above sea level; then after joining the Perené River at 330 m (1,080 ft) above sea level, it becomes the Tambo River; when it joins the Urubamba at 280 m (920 ft) above sea level the river becomes the Ucayali, which is the main headstream of the Amazon. Sometimes the complete river from its source to its junction with the Ucayali, including the rivers Ene and Tambo, is called "Apurímac", with a total length of 1,070 km (660 mi).

The Marañón River (Spanish: Río Marañón, IPA: [ˈri.o maɾaˈɲon], Quechua: Awriq mayu) is the principal or mainstem source of the Amazon River, arising about 160 km (100 miles) to the northeast of Lima, Peru, and flowing northwest across plateaus 3,650 m (12,000 feet) high, it runs through a deeply eroded Andean valley, along the eastern base of the Cordillera of the Andes, as far as 5° 36′ southern latitude; from where it makes a great bend to the northeast, and cuts through the jungle Ande in its midcourse, until at the Pongo de Manseriche it flows into the flat Amazon basin. Although historically, the term "Marañón River" often was applied to the river all the way to the Atlantic Ocean, nowadays the Marañón River is generally thought to end at the confluence with the Ucayali River, after which most cartographers label the ensuing waterway the Amazon River.

As the Marañón passes through high jungle in its midcourse, it is marked by a series of unnavigable rapids and falls.

The Tambo River (Spanish: Río Tambo) is a Peruvian river on the eastern slopes of the Andes. The name only refers to a relatively short section of the waterbody; about 159 km (99 mi) long. It starts at the confluence of the Ene and Perené Rivers at the town of Puerto Prado. From here the Tambo flows 70 km (43 mi) in an easterly direction and then turns north. When merging with the Urubamba River at the town of Atalaya, it becomes the Ucayali River.

The Tambo is part of the headwaters of the Amazon River whose origin is the Mantaro River at Cordilerra Ruminator Cruz.

The Urubamba River or Vilcamayo River (possibly from Quechua Willkamayu, for "sacred river") is a river in Peru. Upstream it is called Vilcanota River (possibly from Aymara Willkanuta, for "house of the sun"). Within the La Convención Province, the name changes to Urubamba. A partially navigable headwater of the Amazon River, the Urubamba rises in the Andes to the southeast of Cusco. It originates on the slopes of Cunurana in the Puno Region, Melgar Province, near the La Raya pass. It flows north-north-west for 724 km (450 mi) before coalescing with the Tambo River to form the Ucayali River.

The Urubamba is divided into the Upper Urubamba and the Lower Urubamba, the dividing feature being the Pongo de Mainique, an infamous whitewater canyon, where the river narrows to a width of 45 metres (148 ft).

Pucallpa (Spanish pronunciation: [pu'kalpa], Quechua: puka allpa, lit. 'red dirt'; Shipibo: May Ushin) is a city in eastern Peru located on the banks of the Ucayali River, a major tributary of the Amazon River. It is the capital of the Ucayali region, the Coronel Portillo Province and the Calleria District. This city is categorized as the only metropolis in Ucayali, being the largest populated center of the region. According to the Instituto Nacional de Estadística e Informática, it is the tenth most populated city in Peru and second largest in the Peruvian Amazon after Iquitos. In 2017 it housed a population of 211,611 inhabitants.

Although originally located in the district of Callería, in the 1980s it formed a conurbation with the towns of Puerto Callao (district of Yarinacocha) and San Fernando (district of Manantay, created in 2000).