The Itimbiri River originates in
Bas-Uélé, then flows through
Mongala, and in its lower reaches defines the border between Mongala and
Tshopo. The Itimbiri is formed by the confluence of the
Rubi River and the
Likati River. The
Rubi River originates in the east of Bas-Uélé and flows west through
Buta. The Likati River originates to the west, then flows through
Likati and southeast to join the Rubi.
Likati lies to the south of
Bondo on the
Uele River. The Itimbiri flows in a general southwest direction. Water volumes range from , with the main flood in November and a secondary flood in August, and lowest water in February or early March. The river is very winding and generally has a sandy bottom, apart from the section upstream from Ibembo, where the bottom is very hard gravel. During low water the river widens and splits into several branches, making navigation by large vessels difficult. The average elevation is . ==Biology==