West Siberian Plain
West Siberian Plain, an extensive region of continuous flatland, N Asia, comprising the western third of Siberia, Russia. It is bounded on the east by the Yenisei River, on the north by the Arctic Ocean, on the west by the Urals, and on the south by Kazakh hill country and the Altai Mts. Tundra and taiga cover the northern section, while the southern section is steppe. It was the source of most of the USSR's oil and gas production during the 1970s and 80s.