Severo-Sakhalin Plain

(North Sakhalin Plain), a low plain in the northern part of the island of Sakhalin. The Seve-ro-Sakhalin Plain is 300 km long and about 100 km wide. The Okha Isthmus in the north narrows to 6–7 km. For significant distances along the coastline there are chains of lagoons separated from the sea by spits. The coastal lowlands are divided by two parallel hilly regions, which have elevations to 200 m and lie on northern continuations of the Zapadnyi Sakhalin Mountains and the Vostochnyi Sakhalin Mountains. Low mountain ridges, including the Dagi (Mount Daakhuria, elevation of 601 m), Vagis (538 m), and Ossoi (386 m), are located in the region. The plain is composed of sands, clays, and gravels of the Neo-gene and Anthropogene. The lower courses of the Tym’ and Nabil’ rivers are situated in the southeast; the Nysh River flows into the Tym’ from the left. The shores are marshy and occupied mostly by open woodlands; the interior regions are open larch taiga with some spruce and fir. Petroleum and gas are extracted. There is hunting and reindeer breeding in the region.