The region is about 1,500 km long and 250 km wide, stretching from the Yarlung Tsangpo river valley in Tibet in the southwest, to the Qilian Mountains of Gansu Province in the northeast. The strip of land forms a high plain over 4,000 meters in elevation. The plateau is inclined slightly from northweast to southeast. Both the Yellow River and the Yangtze River have their headwaters in the eastern extent of this ecoregion.