The Mamoré is a large river in Bolivia

Bolivia

Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...

 and Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

, which unites with the Beni

Beni River

The Beni River is a river in the north of Bolivia.It rises north of La Paz and flows northeast through the pampas. One of the tributary rivers is Tuichi River in the Madidi National Park. Tuichi River joins the Beni River upstream from the town Rurrenabaque. South of Rurrenabaque, Río Beni runs...

 to form the Madeira

Madeira River

The Madeira River is a major waterway in South America, approximately 3,250 km miles long The Madeira is the biggest tributary of the Amazon...

, one of the largest tributaries of the Amazon

Amazon River

The Amazon of South America is the second longest river in the world and by far the largest by waterflow with an average discharge greater than the next seven largest rivers combined...

. It rises on the northern slope of the Sierra de Cochabamba, east of the city of Cochabamba

Cochabamba

Cochabamba is a city in central Bolivia, located in a valley bearing the same name in the Andes mountain range. It is the capital of the Cochabamba Department and is the fourth largest city in Bolivia with an urban population of 608,276 and a metropolitan population of more than 1,000,000 people...

, and is known as the Chimoré

Chimoré River

Chimoré River is a river in Cochabamba Department, Bolivia....

 down to its junction with the Chapare

Chapare

Chapare may refer to:* Chapare Province, Bolivia* Chapare RiverIt may also refer to:* Chapare virus...

. Its larger tributaries are the Chapare

Chapare River

The Chapare River is a river in Bolivia, which is a tributary of the Mamoré River in the Amazon River watershed. The river has its source at the confluence of Espíritu Santo River and San Mateo River in the Cochabamba Department at Villa Tunari. It is the main waterway of Chapare Province...

, Secure

Sécure River

-See also:*List of rivers of Bolivia*Isiboro Sécure National Park and Indigenous Territory-References:*Rand McNally, The New International Atlas, 1993....

, Apere

Apere River

The Apere River is a river of Bolivia. It is a tributary of the Mamoré River, in the Department of Beni.-References:*Rand McNally, The New International Atlas, 1993....

 and Yacuma

Yacuma River

The Yacuma River is a river in Bolivia....

 from the west, and the Ichilo, Guapay

Río Grande (Bolivia)

The Río Grande in Bolivia rises on the southern slope of the Sierra de Cochabamba, east of the city of Cochabamba, at . At its source it is known as the Río Rocha and crosses the Cochabamba valley basin in a westerly direction...

, Ivari and Guapore

Guaporé

Guaporé may refer to:*Guaporé River in Brazil/Bolivia*Guaporé, Rio Grande do Sul in Brazil*The former name of Rondônia...

 from the east . Taking into account its length only, the Guapay should be considered the upper part of the Mamore; but it is shallow and obstructed, and carries a much smaller volume of water. The Guapore, or Itenez, also rivals the Mamore in length and volume, having its source in the Serra dos Parecis, Mato Grosso

Mato Grosso

Mato Grosso is one of the states of Brazil, the third largest in area, located in the western part of the country.Neighboring states are Rondônia, Amazonas, Pará, Tocantins, Goiás and Mato Grosso do Sul. It also borders Bolivia to the southwest...

, Brazil, a few miles from streams flowing north-ward to the Tapajos

Tapajós

The Tapajós, a Brazilian river running through a humid and hot valley, pours into the Amazon River 500 miles above Pará and is about 1200 miles long.It rises on the lofty Brazilian plateau near Diamantino in 14 degrees 25' south latitude...

 and Amazon, and southward to the Paraguay

Paraguay River

The Paraguay River is a major river in south central South America, running through Brazil, Bolivia, Paraguay, and Argentina...

 and Paraná

Paraná River

The Paraná River is a river in south Central South America, running through Brazil, Paraguay and Argentina for some . It is second in length only to the Amazon River among South American rivers. The name Paraná is an abbreviation of the phrase "para rehe onáva", which comes from the Tupi language...

 rivers. The Mamore is interrupted by rapids a few miles above its junction with the Beni, but a railway 300 km long has been undertaken from below the rapids of the Madeira. Above the rapids the river is navigable to Chimore

Chimoré

Chimoré may refer to:*Chimoré River, Bolivia*Chimoré, Cochabamba, Bolivia*Chimoré, Santa Cruz, Bolivia...

, at the foot of the sierra, and most of its tributaries are navigable for long distances. Franz Keller (see References) gives the outflow of the Mamore at mean water level, and not including the Guapore, as 2,530 cub. in. per second, and the area of its drainage basin, also not including the Guapore, as 9,382 m².