The Custom house, Chittagong is the largest custom station in Bangladesh, located by the estuary of the Karnaphuli River in Patenga, near the city of Chittagong. It is a tidal seaport dominated by trade in containerised products. It is one of the two main sea ports of Bangladesh - most of the export and import of the country are handled via this port. The history of Chittagong port dates back to the fourth century B.C. Malayan history chronicles the journey of the sailor Buddha Gupta from Chittagong to Malaya in the 4th century B.C. The Periplus of the Erythraean Sea documents the existence of Chittagong port in the ancient times.