Chittagong (or Chattogram) is situated on the banks of the Karnaphuli River between the Chittagong Hill Tracts and the Bay of Bengal. Karnaphuli is the largest and most important river in Chittagong that originates from Mizoram (India) and flows southwest into the Bay of Bengal. Chittagong city port is the busiest international seaport on the Bay of Bengal and the third busiest in South Asia.