South Tibet is a literal translation of the Chinese term Zàngnán (藏南), which may refer to different geographic areas:
The southern part of Tibet, covering the middle reaches of the Yarlung Tsangpo River Valley between Saga County to the west and Mainling County to the east, as well as neighbouring areas located between the Himalayas to the south and the Transhimalayas range to the north. The region extends around 1,000 km from west to east and 300 km from north to south. By this definition, South Tibet includes most of modern-day Shigatse, Lhasa, Lhoka Prefecture and Nyingchi Prefecture.
South Tibet may also refer to a shorter section of the Yarlung Tsangpo and tributaries covering most of Lhoka and Nyingchi Prefectures from the confluence with the Lhasa River to the west up to the beginning of the Yarlung Tsangpo Grand Canyon near Mainling County to the east.
When used in relation to the Sino-Indian border dispute, South Tibet is a term mainly used by the China to refer to the territories located south of the McMahon Line, established through the Simla Accord (1914), administered by India as part of the state of Arunachal Pradesh and claimed by both the People's Republic of China and the Republic of China (Taiwan).
By extension, South Tibet may also refer to the entire state of Arunachal Pradesh as claimed by China, although the disputed areas do not cover its entire territory.
