Mandakini is a tributary of the Alaknanda River. Mandakini originates from the Chorabari Glacier near Kedarnath in Uttarakhand, India. Mandakini is fed by Vasukiganga River at Sonprayag. Mandakini joins Alaknanda at Rudraprayag. Alaknanda then proceeds towards Devaprayag where it joins with Bhagirathi River to form the Ganges River. Mandakini river flows along NH-109 in Rudraprayag district and turns violent during monsoon, often destroying parts of the highway and adjoining villages.