|Countries||Ghana, Burkina Faso, Togo, Benin|
|- elevation||150 m (492 ft)|
|Mouth||Lake Volta of Ghana|
|- location||Gulf of Guinea|
|Length||520 km (323 mi)|
|Basin||72,000 km2 (27,799 sq mi)|
The Oti River is about 520 km (323 mi) long. Its headwaters are in Burkina Faso, it flows through Benin and Togo and joins the Volta River in Ghana. Tributaries on the left bank in Togo originate from the Togo Mountains to the south. One of its eastern tributaries is the Kara River, the confluence being on the Togo/Ghana border, where another tributary joins from the south, the Koumongou River. The mouth of the Oti was formerly on the Volta River, but it now flows into Lake Volta reservoir in Ghana.
The river crosses the northern part of Togo in a savannah-clad valley some 40 or 50 km (25 or 31 mi) wide. Along the margins of the river is gallery forest which floods periodically. The dry season here lasts from about November until April, with the hot dry Harmattan wind blowing from the north. At this time of the year the river's flow is minimal. Both the Oti and the Koumongou have floodplains, some 10 and 4 km (6.2 and 2.5 mi) wide respectively. These flood extensively during the wet season, but during the dry season they become dry, dusty plains, with the occasional pond or lake in a depression. Cattle graze on the floodplains during the dry season. There is also some small scale growing of crops, and the hunting of game takes place there.