 The mainstem, "Bhilangna", rises at the foot of the Khatling Glacier (elevation ) approximately south of the ice cave at Gaumukh, traditionally considered the source of both the Bhagirathi and the Ganges and flows into the Bhagirathi at Old Tehri, the site of the Tehri dam.It meets its major tributary the "Bal Ganga" at Ghansali (elevation ).The "Bal Ganga", whose headwaters are formed at the foot of Mount Kukhli Dhar (elevation ), itself has a minor tributary, the "Dharam Ganga", which meets it at Thati Kathur (also Budha Kedar) at elevation 

The Khatling trek route passes alongside the Bhilangna, starting from the last point accessible by road, Ghuttu, until the glacier, which stands at 3700 metres.