The Karnaphuli River is the largest and most important river in Chittagong and the Chittagong Hill Tracts. It is a 667-metre (2,188 ft) wide river in the south-eastern part of Bangladesh. Originating from the Saithah village of Mamit district in Mizoram, India, it flows 270 kilometres (170 mi) southwest through Chattogram Hill Tracts and Chattogram into the Bay of Bengal. It is the fastest flowing river in Bangladesh, after the Padma. It is said to "represent the drainage system of the whole south-western part of Mizoram." Principal tributaries include the Kawrpui River or Thega River, Tuichawng River and Phairuang River. A large hydroelectric power plant was built on the Karnaphuli in the Kaptai region in the 1960s. The mouth of the river hosts the Port of Chattogram, the largest and busiest seaport of Bangladesh.
