Kolyma Upland, mountain tract in northeastern Siberia, Russia. It lies along the northeastern shores of the Sea of Okhotsk, which it separates from the extensive Kolyma Lowland that drains northward to the East Siberian Sea. A confused mass of ranges and uplands cut by deep river valleys and gorges, the area has several peaks over 5,000 feet (1,500 m). The sparsely populated area comprises desolate tundra, but gold mining is important in the valley of the upper Kolyma River.