The Barak River is one of the major rivers of South Assam and is a part of the Surma-Meghna River System. It rises in the hill country of Manipur State, where it is the biggest and the most important of the hill country rivers. After Manipur it flows through Mizoram State and into Assam, ending just after it enters Bangladesh where the Surma and Kushiyara rivers begin.
From its source in the Manipur Hills of India, Liyai Village of Poumai Naga tribe, the river is known as the Barak River. Near its source, the river receives a lot of little hill streams, including the Gumti, Howrah, Kagni, Senai Buri, Hari Mangal, Kakrai, Kurulia, Balujhuri, Shonaichhari and Durduria. It flows west through Manipur State, then southwest leaving Manipur and entering Mizoram State.
In Mizoram State the Barak flows southwest then veers abruptly north when joined by a north flowing stream and flows into Assam State where it turns westward again near Lakhipur as it enters the plains. It then flows west past the town of Silchar where it is joined by the Madhura River. After Silchar, it flows for about 30-odd kilometres and just west of Badarpur, it enters Bangladesh and at its mouth divides into the Surma River and the Kushiyara River. The principal tributaries of the Barak are all in India and are the Jiri, the Dhaleshwari (Tlawng), the Singla, the Longai, the Madhura, the Sonai (Tuirial), the Rukni and the Katakhal.