The principal tributaries are all in India: the Irang, Tuivai, Sonai (or Tuirial), the Jiri, the Tlawng (or Dhaleswari, or Katakal), the Jatinga, the Longai and the Madhura.

[6] From its source at Liyai Kullen Village[citation needed] in the Manipur state where most people are of the Poumai Naga tribe, the river is known as Vourei.

Near its source, the river receives streams such as the Vehrei originating from Phuba Village, the Gumti, Howrah, Kagni, Senai Buri, Hari Mangal, Kakrai, Kurulia, Balujhuri, Shonaichhari and Durduria.

The local rainfall run off of the valley along with that of adjacent hilly areas flows through river Barak and its various tributaries and is drained out to Bangladesh.

From here the flow is westward into Cachar, then Karimganj District of Assam, then to Sylhet in Bangladesh having a co-distributary the Surma River, the other later becoming the Meghna before the Ganga-Brahmaputra delta.

Prominent nature conservation NGO Society for Activists for Forest and Environment (SAFE) has pointed out that the tribals living on both banks of Barak have developed the harmful practice of blasting small gelatin sticks smuggled from Mizoram to kill fish.

“Factors like poaching (for oil and meat) and accidental mortalities in fishing gear, gradual habitat degradation by sluice gates, embankments, disturbances like motorboats and aquatic pollution have resulted in the extirpation of the resident dolphin population from the Barak river system of Assam,” M.K.