Tangail District is flanked on the west by the mighty river Jamuna, which is nowhere less than 4 miles wide during the rainy season. The Dhaleshwari, first an old channel of the Ganges and then of the Brahmaputra, cuts across the south-western corner of the district on its powerful sweep to join the Meghna near Narayanganj. The old name of Dhaleshwari was "Gajghata". It used to flow afterwards by the Salimabad Channel and then at last by Porabari Channel. A part of the eastern boundary of the district runs close to the Banar River. The river Bangshi flows almost down the middle of the district, branching out from the old Brahmaputta to the north from near Jamalpur. Bangshi falls into Dhaleswari near Savar, in Dhaka district. The Bangshi forms a natural barrier to the Madhupur Jungle on the Tangail side, all the way from Madhupur to Mirzapur. It is fordable at only two or three places near Basail on its my to river Meghna. Dhaleswari itself however takes out from the Jamuna from inside Tangail district.