Bairi Tibetan Autonomous County (Tibetan: དཔའ་རིས་བོད་རང་སྐྱོང་རྫོང༌།), also known as Tianzhu from its Chinese name (Chinese: 天祝藏族自治县), is in the prefecture-level city of Wuwei in the central part of Gansu province, China, bordering Qinghai province to the south and west.

The Chinese name "Tianzhu" was named by a Tibetan lama Luo Haoxue (罗好学) in 1936, deriving from the combination of "Tiantang" (天堂寺, aka Chortentang Monastery) and "Zhugong" (祝贡寺, aka Drigung Monastery), the Chinese translation of the two largest lamaseries in the county.

In 1955, Tianzhu was moved under the administration of Zhangye as the first autonomous county in China.

[4] Bairi Tibetan Autonomous County is divided to 14 towns, 5 townships.

[4][5] The county is mountainous, being located at the tripoint of the Tibet Plateau, the Loess Plateau and the Inner Mongolia Plateau, with elevations ranging from 2040 m to 4874 m. It is divided into the watersheds of the Shiyang River and the Yellow River and crossed by the Wushao Mountain.