Puhar (also known as Poompuhar) is a town in the Nagapattinam district in the southern Indian state of Tamil Nadu. It was once a flourishing ancient port city known as Kaveri poompattinam, which for a while served as the capital of the Early Chola kings in Tamilakam. Puhar is located near the end point of the Kaveri river, aside from the sea coast. It is mentioned in the Periplus of the Erythraean Sea. It has now been established by marine archaeological research (conducted by the National Institute of marine archaeology, Goa) that much of the town was washed away by progressive erosion and floods. In the sixties and seventies of 20th Century, Archaeological researches were conducted under the leadership of the noted archaeologist Dr. K. V. Soundararajan. Submerged wharves and several meter lengths of pier walls excavated in recent times have corroborated the literary references to Poompuhar. It was rebuilt several times after that. Ancient Pottery dating back to the 4th century BCE have been discovered offshore by marine archaeologists east of this town.