The Yili Basin is located in the most northwestern part of China, west of the city of Ürümqi 烏魯木齊 (Urumchi, Wulumiqi). The River Yili (old: Ili) spring off the Tianshan Mountain 天山 range and flows to the west into Lake Balkhash (Chinese: Barkashi Hu 巴爾喀什湖) in modern Kazakhstan. The most important city of this area is the border post Yining 伊寧 (Ningyuan 寧遠; Kuldja). From the Han period the area was inhabited by the Wusun 烏孫 tribes, from the 6th century on by various Turkic federations. The Tang Dynasty incorporated this area into their Western Protectorate 安西都護府. In the 10th century the Yili Basin became part of the Karakhan Empire 黑汗王朝, during the Mongol period it was reigned as khanate (Mongol: ulus) of the Chagatai Khans (Chahetai Hanguo 察合台汗國). After the Yuan Dynasty it was territory of the Oirat Mongols (Weilute Menggu 危魯特蒙古) and was administered as Mongol-Turk-Uighur balik territory of Ili (Yili bali 亦力把里). The Qing government installed a military prefecture in this area that was an important post for the administration of the western area and as trade post between China and Russia. When a Muslim rebellion under Jakub Beg broke out in 1864 the Russians occupied the Ili Basin and forced the Chinese government to cede this territory in 1876.