Bosten Lake (Chinese: 博斯騰湖; pinyin: Bósīténg Hú, Uyghur: باغراش كۆلى / Baghrash Köli/Baƣrax Kɵli) is a freshwater lake located on the northeastern rim of the Tarim Basin, about 20 km (12 mi) east of Yanqi and 57 km (35 mi) northeast of Korla, Xinjiang, China in the Bayin'gholin Mongol Autonomous Prefecture. Covering an area of about 1,000 km2 (390 sq mi) (together with adjacent small lakes), it is the largest lake in Xinjiang and one of the largest inland freshwater lakes in China. Bosten lake receives water inflow from a catchment area of 56,000 km2 (22,000 sq mi).
The lake's Uyghur and Chinese names are sometimes rendered as Bosten Hu, Bagrax-hu, Bagrasch-köl, Baghrasch köl, Bagratsch-kul, Bositeng Lake or Bositeng Hu.
The Kaidu River is the most important tributary to Lake Bosten, accounting for about 83% of its water inflow, other significant tributaries are the Huang Shui Ditch (Chinese: 黃水溝), the Qing Shui River (Chinese: 清水河), and Wu-La-Si-Te River (Chinese: 烏拉司特河).