Kaptai Dam (Bengali: কাপ্তাই বাঁধ) is on the Karnaphuli River at Kaptai, 65 kilometres (40 mi) upstream from Chittagong in Rangamati District, Bangladesh. It is an earth-fill embankment dam with a reservoir (known as Kaptai Lake) water storage capacity of 6,477 million cubic metres (5,251,000 acre·ft). The primary purpose of the dam and reservoir was to generate hydroelectric power.