Province (pop., 2002 est.: 5,290,000), northwestern China. It is bordered by Gansu and Sichuan provinces and the Tibet and Xinjiang autonomous regions.With an area of 278,400 sq mi (721,000 sq km), it is the fourth largest political subdivision in China. The capital is Xining. Located in a remote region west of the historic provinces of China proper, it forms the northeastern part of the Plateau of Tibet, mostly above 13,000 ft (4,000 m) in elevation. The source of the Huang He (Yellow River) is in one of its mountain ranges. Parts of Qinghai came under Chinese control in the 3rd century BC. For centuries it was sparsely occupied by nomadic herdsmen, chiefly Tibetans and Mongols, and a few Chinese farmers. The Chinese population increased over the years. Qinghai was made a Chinese province in 1928. Economic activities today include farming, herding, mining, lumbering, and manufacturing. It possesses some of China's best pasturelands and is noted for its horse breeding.