The river Yamuna flows along its eastern boundary. The ancient Sarasvati River was thought to have flowed through Haryana, but it has now disappeared.
The river Ghaggar is Haryana's main seasonal river. The Ghaggar rises in the outer Himalayas, between the Yamuna and the Sutlej and enters Haryana near Pinjore, district Panchkula. Passing through Ambala and Hissar, it reaches Bikaner in Rajasthan and runs a course of 290 miles before disappearing into the deserts of Rajasthan.
The Markanda river's ancient name was Aruna. A seasonal stream like the Ghaggar, it originates from the lower Sivalik Hills and enters Haryana near Ambala. During monsoons, this stream swells into a raging torrent notorious for its devastating power. The surplus water is carried on to the Sanisa lake where the Markanda joins the Sarasvati.
An important tributary is the Tangri. The Sahibi originates in the Mewat hills near Jitgarh and Manoharpur in Rajasthan. Gathering volume from about a hundred tributaries, it reaches voluminous proportions, forming a broad stream around Alwar and Patan. On reaching Rohtak it branches off into two smaller streams, finally reaching the outskirts of Delhi and flowing into the Yamuna. There are three other rivulets in and around the Mewat hills – Indori, Dohan and Kasavati and they all flow northwards from the south.