The Brahmaputra-Jamuna is the second largest river in Bangladesh and one of the largest rivers in the world, flowing through Tibet, China, India and Bangladesh. Actually Jamuna is the downstream course of the brahmaputra which took place after the earthquake and catastrophic flood between 1782-1787. Presently the Brahmaputra continues southeast from Bahadurabad (Dewanganj upazila of Jamalpur district) as the old brahmaputra and the river between Bahadurabad and Aricha is the Jamuna, not Brahmaputra. The Hydrology Directorate of the bangladesh water development board (BWDB) refers to the whole stretch as the Brahmaputra-Jamuna.
It originates in the Chemayung-Dung glacier, approximately at 31'30'N and 82'0'E, some 145 km from Parkha, an important trade centre between lake Manassarowar and Mount Kailas. The Brahmaputra is known as the Dihang in Assam Himalayas before it comes into the Great Plains of Bengal. It enters Bangladesh through Kurigram district (at the border of Kurigram Sadar and Ulipur upazilas). The total length of the Tsangpo-Brahmaputra-Jamuna river up to its confluence with the Ganges is about 2,700 km. Within Bangladesh territory, Brahmaputra-Jamuna is 276 km long, of which Jamuna is 205 km.