Karnaphuli ( Kôrnophuli; also spelt Karnafuli), or Khawthlangtuipui (in Mizo, meaning western river), is the largest and most important river in Chittagong and the Chittagong Hill Tracts. It is a wide river in the south-eastern part of Bangladesh. Originating from the Saithah village of Mamit district in Mizoram, India, it flows southwest through Chittagong Hill Tracts and Chittagong into the Bay of Bengal. 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 using Karnaphuli river was built in the Kaptai region during the 1960s. The mouth of the river hosts Chittagong's sea port, the largest and busiest sea port of Bangladesh.