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
Arkhangelsk Oblast the 1970s and is expected to become part of the Belkomur project — a railway line connecting Arkhangelsk via the Komi Republic with the Perm Krai and the Ural mountains. Almost the entire rail network belongs to the Northern Railway, which west of Onega connects to the Oktyabrskaya Railway. There is also a railway line from Severoonezhsk west to Yangory (an extension of the line from Puksa to Navolok), which belongs to the Department of Corrections. A big number of narrow gauge railways have been built in the 1950s and 1960s to facilitate the transport of timber, but since then