Saraswati River is believed to have drained the north and northwest region of India, including Haryana and Punjab, in ancient times, supporting a large number of settlements. There are numerous references to the river Saraswati in the ancient Indian literature of the Vedic and post-Vedic period. Rig Veda, the most ancient of the four Vedas, describes Saraswati as a mighty river with many individually recognized tributaries. The sacred book calls Saraswati as the seventh river of the Sindhu-Saraswati river system, hence the name 'Saptsindhu' for the region bounded by rivers Saraswati in the east and Sindhu (Indus) in the west. Rig Veda hymns also describe life and times of the people residing in the Saraswati river valley. Rig Veda describes Saraswati as Ambitamé, the best of the mothers; Naditamé, the best of the rivers; and Devitamé, the best of the goddesses. Ancient sites in Kunal and Banawali, in district Fatehbad, has been found on the banks of the dried river bed of Saraswati.
Saraswati is believed to have originated from the Har-ki-Dun glacier in west Garhwal (Uttaranchal). It flowed parallel to the river Yamuna for some distance and later joined it, proceeding south as the Vedic Saraswati. The seasonal rivers and rivulets, including Ghaggar, joined Saraswati as it followed the course of the present river through Punjab and Haryana. River Sutluj, the Vedic Shatadru, joined the river Saraswati as a tributary at Shatrana, approximately 25 km south of Patiala. Saraswati then followed the course of Ghaggar through Rajasthan, Gujarat and Hakra in Bhawalpur before emptying into the Rann of Kutch via Nara in Sindh province, running parallel to the Indus River. It has been established that the river Saraswati, carrying the waters of three perennial and numerous seasonal rivers, was a mighty river in the Vedic times.
As of today, a part of the river exists as Ghaggar in Haryana; the rest of it has disappeared in the fringes of the desert of Rajasthan, Gujarat and Sindh. The perennial rivers Sutluj and Yamuna were once the tributaries of the Saraswati. It is believed that subsequently some tectonic movements may have forced the Sutluj and Yamuna to change course and hence Saraswati dried up in a period spread over a few hundred years possibly between 2000 and 1500 BC. It is probable that desertification of Rajasthan would have taken place at that time. The present dried bed of the Ghaggar was thus part of a major river, anciently known as Saraswati. Analysis of satellite imagery supports the above hypothesis regarding the course of the 'lost' Saraswati.