Tanggula Mountains in the context of "Nagqu Prefecture"

The Yangtze River, Yangzi River (English: /ˈjæŋtsi/ or /ˈjɑːŋtsi/) or Chang Jiang (simplified Chinese: 长江; traditional Chinese: 長江; pinyin: Cháng Jiāng; lit. 'long river') is the longest river in China and the third-longest river in the world. It rises at Jari Hill in the Tanggula Mountains of the Tibetan Plateau and flows, 6,374 km (3,961 mi) including the Dam Qu River, the longest source of the Yangtze, in a generally easterly direction to the East China Sea. It is the fifth-largest primary river by discharge volume in the world. Its drainage basin comprises one-fifth of the land area of China, and is home to nearly one-third of the country's population.

The Yangtze has played a major role in the history, culture, and economy of China. For thousands of years, the river has been used for water, irrigation, sanitation, transportation, industry, boundary-marking, and war. The Yangtze Delta generates as much as 20% of China's GDP, and the Three Gorges Dam on the Yangtze is the largest hydro-electric power station in the world. In mid-2014, the Chinese government announced it was building a multi-tier transport network, comprising railways, roads and airports to create a new economic belt alongside the river.

The Dangqu, Dam Qu (Chinese: 当曲, p Dāngqū) or Dam Chu (Tibetan: འདམ་ཆུ, w 'Dam Chu, lit. "Marshy River") is the longest source of the Yangtze River, with a total length of 365.7 km (227.2 mi) located in the Qinghai province of the People's Republic of China. It runs from its source in an eastern offshoot of the Tanggula Mountains (唐古拉山), receives its main tributary the Buqu-Gar Qu River (布曲), and has a confluence with the Ulan Moron, where the Tongtian River is formed. The Dangqu has been discovered to be the actual and the longest headwater of the Yangtze River under modern criteria, although the nearby Ulan Moron or Tuotuo was traditionally regarded as the primary river of the two.

Tanggulashan (simplified Chinese: 唐古拉山镇; traditional Chinese: 唐古拉山鎮; pinyin: Tánggǔlāshān Zhèn; lit. 'Tanggula Mountains town', Standard Tibetan: གདང་ལ་གྲོང་རྡལ།), or Dangla Town, is a town in the southwest of Qinghai province, China. It forms the southern exclave of the county-level city of Golmud, in Haixi Mongol and Tibetan Autonomous Prefecture, partially administrated by Amdo County, Tibet Autonomous Region since 1963 and still officially a territory of Yushu Prefecture, Qinghai under trust administration of Golmud, Haixi Prefecture, Qinghai. Before the local administrative reform of 2005, it was known as Tanggula Township (唐古拉乡). It is the only place in China simultaneously under jurisdiction of three prefectures.

The town spans an area of approximately 48,000 square kilometres (19,000 sq mi), and has a population of 1,750 as of 2020.