Saraswati is an ancient river that flowed in northern India during the vedic era.Saraswati is no longer in existence and is said to have originated from Saraswati-Rupin Glacier confluence at Naitwar in Uttaranchal. There are numerous references to the River Saraswati in the ancient and Vedic texts. Saraswati is also said to join the Ganga and Yamuna rivers at Prayag/Allahabad making it the holiest of all confluences that leads to salvation of human soul.
It is believed that Saraswati had three tributaries Sutlej, Drishadvati and Yamuna. They flowed together along a channel, presently known as the Ghaggar River. The river finally ended in the Arabian Sea through the Rann of Kutch. Saraswati was considered the seventh river of the Vedic Sapta Sindhu river system.
Legends state that Aryans fought with the non-Aryan tribes on the banks of River Saraswati. Lord Vishnu requested Saraswati to disappear underground. Thus, the tribals were deprived of water and were forced to abandon the area. So Saraswati is also known as Prithudhar (subjugator of Aryans).
The Triveni Sangam in Allahabad is a confluence of 3 rivers, the Ganges, Yamuna, and Saraswati,of these three The legendary Saraswati River is invisible and is said to flow underground and join the other two rivers from below and the point of confluence is a sacred place for Hindus.