Qinghai is an inland province in Northwestern China. It is the largest province of China by area and has the third smallest population. Its capital and largest city is Xining. Qinghai borders Gansu on the northeast, Xinjiang on the northwest, Sichuan on the southeast and the Tibet Autonomous Region on the southwest. Qinghai province was established in 1928 during the period of the Republic of China, and until 1949 was ruled by Chinese Muslim warlords known as the Ma clique.