Bhilangna River in Uttarakhand India is a major tributary of Bhagirathi River, which is the source-stream of Ganga River. The length of this river is 80 km. Bhilangna River rises at the foot of Khatling Glacier, perched at an elevation 3,717 metres, about 12,195 feet above sea level. The river is approximately 50 km south Gaumukh, which is considered as the traditional source of Bhagirathi and Ganga rivers. It flows into Bhagirathi at Old Tehri, the site of the Tehri Dam.
Bhilangna meets its major tributaries namely Bal Ganga at Ghyansali at 976 metres about 3,202 feet above sea level. The popular Khatling trek route also passes alongside Bhilangna River. Ghansali town, Ghuttu, Reeh, Gangi, Biroda, Kalyani, Kharsali, Bhelbagi, Tamabakund, Ghonti etc. are the major towns which are situated on the banks of Bhilangana River.