The river Phalgu (or Falgu) which flows past Gaya, India in the Indian state of Bihar, is a sacred river for Hindus. The Phalgu is formed by the junction, some 3 kilometres (2 mi) below Bodh Gaya, of the Lilajan (also called Niranjan or Nilanjan) and the Mohana, two large hill streams each of which is over 270 metres wide.The Phalgu is also mentioned as Niranjan.The united stream flows on to the north past the town of Gaya, where it attains a breadth of over 820 metres. The Phalgu here passes by a high rocky bank, on the steep sides of which are many paved stairs leading down to the river bed, while high above are the Vishnupad Mandir, with many minor shrines around it. It then runs in a north-easterly direction for about 27 kilometres, and opposite the Barabar hills it again takes the name of Mohana, and divides into two branches which eventually flow into a branch of the Punpun.
The Phalgu like its confluent streams, Lilajan and Mohana, is subject to high floods during the monsoons but in other seasons of the year it dwindles to a stream wandering through a wide expanse of sand.