Arkhangelsk Oblast the south-west of the Oblast drains into the Kema River which belongs to the basin of the Caspian Sea. The area in the Onega River basin containing the biggest lakes in the oblast, such as Lake Lacha, Lake Kenozero, Lake Undozero, and Lake Kozhozero. The tundra of the Nenets Autonomous Okrug also contains a number of bigger lakes. The river basin of the Pinega is characteristic of the karst, with a number of caves in the region. The White Sea coast within the Oblast is split into the Onega Bay (where the Onega is the major tributary), the Dvina Bay
Onega Bay descendants) not later than in the 12th century. The selo of Soroki, currently Belomorsk, is known from that time. Most of the villages at the Onega Bay coast such as Purnema or Unezhma (now abandoned), are old Pomor villages, many of them still depend on fishery. Solovetsky Islands are on the World Heritage list, and there is intensive passenger sea traffic to the islands, mostly originating from Kem and Belomorsk. There are also regular but infrequent passenger connections between Arkhangelsk and the villages of the Onega Peninsula. Onega Bay The Onega Bay () is located in the Republic of Karelia