See also: Oka (river).
| Oka | |
| Source1 Location: | Oka Plateau, Sayan Mountains |
| Mouth: | Angara |
| Mouth Location: | Bratsk Reservoir |
| Mouth Coordinates: | 55.5153°N 102.3483°W |
| Subdivision Type1: | Country |
| Subdivision Name1: | Russia |
| Length: | 630km (390miles) |
| Basin Size: | 34000km2 |
| Pushpin Map: | Russia Irkutsk Oblast |
| Pushpin Map Caption: | Mouth location in Irkutsk Oblast, Russia |
The Oka is a river in Siberia, left tributary of the Angara. It is long, and has a drainage basin of .
It originates in the Oka Lake, Oka Plateau, Sayan Mountains at the western end of Buryatia. It flows roughly northwestwards with the Bolshoy Sayan to the southwest. After it bends northeastwards the river flows between the Kropotkin Range and the Belskye Goltsy (Бельские Гольцы). After the Khoyto-Oka tributary joins it from the left it enters Irkutsk Oblast and flows in a roughly more northern direction. Finally the Oka discharges into the Bratsk reservoir.[1] [2] [3]