WThe 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.
WLake Kenozero is a freshwater lake, located in the south-west of Plesetsky District of Arkhangelsk Oblast in Russia. It is one of the biggest lakes in Arkhangelsk Oblast and the biggest one in Plesetsky District. The area of the lake is 68.6 square kilometres (26.5 sq mi), and the area of its basin is 5,450 square kilometres (2,100 sq mi). Lake Kenozero is the source of the Kena, a tributary of the Onega. The lake thus belongs to the Onega basin and the White Sea basin.
WLake Kozhozero is a freshwater lake, located in the south of Onezhsky District of Arkhangelsk Oblast in Russia. It is one of the biggest lakes in Arkhangelsk Oblast and biggest one in Onezhsky District. The area of the lake is 97.4 square kilometres (37.6 sq mi), and the area of its basin is 2,560 square kilometres (990 sq mi). Lake Kozhozero is the source of the river Kozha, which is a left tributary of the Onega and thus belongs to the White Sea basin. The lake is located in the remote area and is not connected to the outside world by any all-season roads. It is notable as a location of the Kozheozersky Monastery, known since 1560.
WLake Lacha is a freshwater lake, located in the south of Kargopolsky District of Arkhangelsk Oblast in Russia, 7 kilometres (4.3 mi) south of the town of Kargopol. It is the largest lake in Arkhangelsk Oblast, with a surface area of 334 square kilometres (129 sq mi) and a basin area of 12,600 square kilometres (4,900 sq mi). Lake Lacha is the source of the Onega, one of the major waterways of the White Sea basin.
WLake Lyokshmozero is a freshwater lake, located in the north-west of Kargopolsky District of Arkhangelsk Oblast in Russia. It is one of the biggest lakes in Arkhangelsk Oblast and the second biggest in Kargopolsky District. The area of the lake is 54.4 square kilometres (21.0 sq mi), and the area of its basin is 197 square kilometres (76 sq mi). Lake Lyokshmozero is the source of Lyokshma, a tributary of Lake Lacha. The lake thus belongs to the Onega basin and the White Sea basin.
WLake Undozero is a freshwater lake, located in the west of Plesetsky District of Arkhangelsk Oblast in Russia. It is one of the biggest lakes in Arkhangelsk Oblast and the second biggest one in Plesetsky District. The area of the lake is 44.7 square kilometres (17.3 sq mi), and the area of its basin is 709 square kilometres (274 sq mi). Lake Undozero is the source of the Undosha, which belongs to the river basin of the Onega and thus to the White Sea basin.
WLake Vozhe, also known as Lake Charondskoye, is a lake in the northern part of Vologda Oblast in Russia. The area of the lake is 416 square kilometres (161 sq mi), and the area of its basin is 6,260 square kilometres (2,420 sq mi). The average depth is around 2 metres (6.6 ft). Lake Vozhe drains through the Svid into Lake Lacha, from which the Onega flows out. The lake is located on a flatland and its shores are low-lying and swampy. The biggest swamp, the Charonda Swamp, is located to the southeast of the lake. Around twenty rivers flow into Lake Vozhe, including the Vozhega and the Modlona. The lake freezes up in October - November and stays icebound until May.