布兰科河（Rio Branco）全长350英哩，是内格罗河的主要北部支流，而锯齿山脊的支流将委内瑞拉和圭亚那由巴西分开。其中两道主要支流有Urariquira和将布兰科河跟埃塞奎博河发源地连接的塔库图河。

布兰科河向南流，经过多个水道和潟湖流进内格罗河，直到与Urariquira River的汇流点，河中有不少岛屿，距离河口235英哩有急流。

The Branco River (Portuguese:Rio Branco; Engl: White River) is the principal affluent of the Rio Negro from the north. It is enriched by many streams from the Tepui highlands which separate Venezuela and Guyana from Brazil. Its two upper main tributaries are the Uraricoera and the Takutu. The latter almost links its sources with those of the Essequibo.