At Sonepur, where the Gandak meets the Ganga on Mithila’s western edge, stands the Hariharnath temple — uniting Hari (Vishnu) and Hara (Shiva) in one shrine, traditionally said to have been founded by Rama. Around it gathers the Sonepur Mela, once the largest cattle fair in Asia, held at Kartik Purnima.
Pilgrimage, river-confluence and great fair together make Sonepur one of the storied gathering-places of the region.