Chengguan is a major town in the historical region of Kham in the eastern Tibet Autonomous Region of China. It is the seat of Karub District and Chamdo Prefecture, and had a population of 45,861 in 2010. It is located about 600 km (370 mi) east of Lhasa. By road, the distance is 1,120 km (700 mi) via the southern route or 1,030 km (640 mi) via the northern route. It is at an altitude of 3,230 m (10,600 ft) at the confluence of the rivers Za Qu and Ngom Qu which form the Lancang River (Mekong).