section_path: Geography
section_name: Geography
paragraph_text: Geography
  
  The river originates from several tributaries in the eastern part of the Tibetan Plateau, two of which are commonly referred to as the "source." Traditionally, the Chinese government has recognized the source as the Tuotuo tributary at the base of a glacier lying on the west of Geladandong Mountain in the Tanggula Mountains. This source is found at 33°25′44″N 91°10′57″E / 33.42889°N 91.18250°E and while not the furthest source of the Yangtze, it is the highest source at 5,342 m (17,526 ft) above sea level. The true source of the Yangtze, hydrologically the longest river distance from the sea, is at Jari Hill at the head of the Dam Qu tributary, approximately 325 km (202 mi) southeast of Geladandong. This source was only discovered in the late 20th century and lies in wetlands at 32°36′14″N 94°30′44″E / 32.60389°N 94.51222°E and 5,170 m (16,960 ft) above sea level just southeast of Chadan Township in Zadoi County, Yushu Prefecture, Qinghai. As the historical spiritual source of the Yangtze, the Geladandong source is still commonly referred to as the source of the Yangtze since the discovery of the Jari Hill source.
  
  These tributaries join and the river then runs eastward through Qinghai (Tsinghai), turning southward down a deep valley at the border of Sichuan (Szechwan) and Tibet to reach Yunnan. In the course of this valley, the river's elevation drops from above 5,000 m (16,000 ft) to less than 1,000 m (3,300 ft). Thus, over the first 2,600 km (1,600 mi) of its length, the river has fallen more than 5,200 m (17,100 ft).
  
  It enters the basin of Sichuan at Yibin. While in the Sichuan basin, it receives several large tributaries, increasing its water volume significantly. It then cuts through Mount Wushan bordering Chongqing and Hubei to create the famous Three Gorges. Eastward of the Three Gorges, Yichang is the first city on the Yangtze Plain.
  
  After entering Hubei province, the Yangtze receives water from a number of lakes. The largest of these lakes is Dongting Lake, which is located on the border of Hunan and Hubei provinces, and is the outlet for most of the rivers in Hunan. At Wuhan, it receives its biggest tributary, the Han River, bringing water from its northern basin as far as Shaanxi.
  
  At the northern tip of Jiangxi province, Lake Poyang, the biggest freshwater lake in China, merges into the river. The river then runs through Anhui and Jiangsu, receiving more water from innumerable smaller lakes and rivers, and finally reaches the East China Sea at Shanghai.
  
  Four of China's five main freshwater lakes contribute their waters to the Yangtze River. Traditionally, the upstream part of the Yangtze River refers to the section from Yibin to Yichang; the middle part refers to the section from Yichang to Hukou County, where Lake Poyang meets the river; the downstream part is from Hukou to Shanghai.
  
  The origin of the Yangtze River has been dated by some geologists to about 45 million years ago in the Eocene, but this dating has been disputed.