Internationally famous for Asia's largest cattle fair held on the occasion of Kartik Purnima, it is also the head quarters of Sonepur Anchal. Sonepur is a Nagar Panchayat and is noted for its Railways platform which is one of the largest in India. So far as religious aspect of Sonepur Mela is concerned, special significance is owing to the temple of shree Hariharnath and the site of the battle of Gaj-Grah and rescue of the former by Hari During Kartik Purnima Ganga Snan or ceremonial bathing in the Ganges is held by Hindus to be unusually efficacious. On the day of full moon (Kartik Purnima) immense crowd assembles and take bath. The Mela commences on that day and lasts for more than a fortnight. The Shiva temple, Kali temple and other temples and historical religious monuments are situated here and social and economical activities are at the highest peak during the Mela period. People come here to pay their oblation to the lords and thus its importance is not within Sonepur of Bihar rather it is of India and world fame.