Içana River is a tributary

Tributary

A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...

 of the Rio Negro in South America

South America

South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...

. The river arises in the Guaviare Department

Guaviare Department

Guaviare is a department of Colombia. It is in the southern central region of the country. Its capital is San José del Guaviare. Guaviare was created on July 4, 1991 by the new Political Constitution of Colombia...

 of Colombia

Colombia

Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...

, where it is known as the Isana. It flows east and forms a short part of the international boundary between Colombia 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...

. In Amazonas state, where it is known as the Içana, it flows southeast and into the Rio Negro at São Joaquim, Amazonas.