The Dhalai River (also known as Dhala River) is a trans-boundary river in India and Bangladesh. It rises in the mountains of the Indian state of Tripura. It enters Kamalganj Upazila of Maulvibazar District of Bangladesh. Later, it joins the Manu River in Rajnagar Upazila.[1][2] The co-ordinates of the Dhalai River at Ambassa are 23.55'128'' N and 91.51'204'' E in degrees, minutes and seconds (DMS). It originates from Atharamura Hill and is 117 kilometres (73 mi) long. Some of the popular riverside townships of the Dhalai are the towns of Ambassa, Baralutma and Kamalpur.