Amdo encompasses a large area from the Machu River (Yellow River) to the Drichu river (Yangtze River). Comprising Qinghai, South of Gansu, and North of Sichuan; Qilian mountain to the north separate Gebi desert from Tibetan plateau; Changtang plateau to the west connects to the central Tibet, In the south, Kham, another part of TCA closely link to Amdo; The major area of this vast land is called Qinhai Province nowadays.
It is the home of many important Tibetan Buddhist lamas, scholars who had a major influence on religious development of Tibet, such as: the great reformer Tsongkhapa, the 14th Dalai Lama, and the 10th Panchen Lama. It also contains many great monasteries including Kumbum Jampa Ling Monastery near Xining, Labrang monastery south of Lanzhou, and the Kirti Monasteries of Ngaba and Tewo monastery.
Today, The Han-Chinese is a majority in the eastern part of Qinghai and the provincial capital Xining. The northern part of Qinghai has a Mongol majority. The Tibetan of Amdo are referred to as Amdopa as a regional distinction from the Tibetans of Khampa and Central Tibetan, mainly predominate in the western and southern parts of Qinhai, which are now administered as various Tibetan, Tibetan-Qiang, or Mongol-Tibetan autonomous prefectures.
Due to the geographical isolation of many tribal groups, it naturally formed many different dialect of Tibetan language, however the written Tibetan language is the same throughout the whole Tibetan area.