Its main affluent is the Uaupes, which disputes with the headwaters of the Guaviari branch of the Orinoco the drainage of the eastern slope of the " oriental " Andes of Colombia.
The eastern headwaters of the Senegal thus drain a large area adjacent to the upper Niger.
Pop. of urban district (1901) 5479ï¿½ It has a pleasant undulating site near the headwaters of the river Wey.
To the west of Lake Van, and close to the headwaters of the Murad Su, the eastern branch of the Euphrates, while the most easterly point is situated in a region about 42° 50' E., southward of the same lake.