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, Russia town is also served by the Arkhangelsk–Murmansk rail line, which branches off in Obozerskaya railway station from the railroad between Moscow and Arkhangelsk and runs west to Onega and Belomorsk where it joins the railroad between Petrozavodsk and Murmansk. The railroad was built during World War II to secure the transport of goods from the harbor of Murmansk to central Russia. Onega is connected to Severodvinsk by a road. There are no all-seasonal roads on the left bank of the Onega River. The Onega is navigable downstream from the "selo" of Porog; there is regular passenger navigation. There is also