The Altai Mountains are a mountain range in Central Asia, where Russia, China, Mongolia, and Kazakhstan converge, and where the rivers Irtysh and Ob have their headwaters. The highest summit of the range is Belukha, whose summit reaches 4,506 m above sea level. The massif merges with the Sayan Mountains in the northeast, and gradually becomes lower in the southeast, where it merges into the high plateau of the Gobi Desert. In the southwest, it is separated from the higher Tian Shan range by the Junggar Basin. It spans from about 45° to 52° N and from about 84° to 99° E.