Karnaphuli (Bengali: কর্ণফুলিKôrnophuli; also spelt Karnafuli), the largest and most important river in Chittagong and the Chittagong Hill Tracts, is a 667-metre (2,188 ft) wide river in the south-eastern part of Bangladesh. Originating from the Lushai hills in Mizoram, India, it flows 270 kilometres (170 mi) southwest through Chittagong Hill Tracts and Chittagong into the Bay of Bengal. 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 main port of Bangladesh.
The Kaptai Dam is the location of the Karnafuli Hydroelectric Power Station, constructed in Kaptai in 1962 and the only hydro-electric power plant in the country. An earth-filled dam on the Karnaphuli River, the Kaptai Dam created the Kaptai Lake, which acts as the water reservoir for the hydropower station. The power plant produces a total of 230 megawatts of electricity.