The Lohit River, which name came from the Assamese word Lohit meaning blood, also known as the Zayul Chu by the Tibetans and Tellu by the Mishmis, is a river in China and India, which joins the Brahmaputra River in the state of Assam. It is formed in the Zayul County of the Tibet Autonomous Region, through a merger of two rivers: the Kangri Karpo Chu, which originates in the Kangri Karpo range, and Zayul Chu, which originates to its northeast. The two rivers merge below the town of Rima. The combined river descends through this mountainous region and surges through Arunachal Pradesh in India for 200 kilometres (120 mi) before entering the plains of Assam where it is known as the Lohit River. Tempestuous and turbulent, and known as the river of blood partly attributable to the lateritic soil, it flows through the Mishmi Hills, to meet the Siang (Brahmaputra) at the head of the Brahmaputra valley.

Kangri Karpo, also spelt Gangri Garbo, is a mountain range in eastern Tibet, located primarily in Nyingchi Prefecture as well as a portion of Qamdo Prefecture in the Tibet Autonomous Region, China. The mountain range lies to the east of the Himalayas and to the west of the Hengduan Mountains. The mountains are geographically a southern extension of the eastern Transhimalayas.