The Onega is a river in Kargopolsky, Plesetsky, and Onezhsky Districts of Arkhangelsk Oblast in Russia. The Onega connects Lake Lacha with the Onega Bay in the White Sea southwest of Arkhangelsk, flowing in the northern direction. The discharge at the source is 74.1 cubic metres per second (2,620 cu ft/s) and at the mouth is 505 cubic metres per second (17,800 cu ft/s). The river is 416 kilometres (258 mi) long, and the area of its basin 56,900 square kilometres (22,000 sq mi). Its main tributaries are the Voloshka (right), the Kena (left), the Mosha (right), the Kodina (right), and the Kozha (left). The major tributary of the Lake Lacha is the Svid.