Singeshwar temple is a temple of Lord Shiva. This is one of the ancient Shiva temples in Bihar that is visited by several pilgrims throughout the year, though it is not easily accessible from the other parts of Bihar.

According to the legend the Shiva linga was installed by Sringa Rishi who had performed the Putreshti Yajna for king Dasaratha. The present temple over the ancient lingam was constructed around two hundred years back by a merchant of Bhagalpur known as Hari Charan Choudhury. Barak Puran has a different story:-Once upon a time Lord Shiva went to Slesh Atmak forest and told Nandishwar that he should not disclose to anybody where he had gone. Lord Indra with Lord Brahma and Lord Vishnu went to Mount Munjwan and asked Nandishwar about the whereabouts of Lord Shiva. Nandishwar never divulged anything. Then the three gods went to the Slesh Atmak forest to search him. Lord Shiva disguised as a deer. The three gods on recognising him ran to catch hold of him. Indra caught the front portion of the horn, Brahma its middle portion and the root was caught by Lord Vishnu. The deer disappeared when the horn broke into three pieces.

Thereafter they heard a voice from the heaven saying that they would not be able to find Lord Shiva and need to be satisfied with the portion of the horn in their hands. Lord Indra established the portion of the horn in heaven. Lord Brahma established it at that very place. These parts came to be known as Kokaran. Lord Vishnu established on earth for the good of humanity and this came to be known as Singheshwar.

This Shiva temple is also called Singheshwarsthan. This place is considered to be the most pious for the Hindus. It is believed that during the period of Ramayana Putreshthee Yagya was performed by Raja Dashratha and he was blessed with four sons from the prasad "Charu" of that mahayagya. The great Sringhi Rishi worshipped Lord Shiva on the occasion of that yagna. The Seven "Havana Kunds" that was created at that time has been converted into a ravaged tank now. Mahashivratri Mela (which is one of the Rajkiya Mela of Bihar) of Singheshwarasthan is eminent.

Varaha Purana has also references to Singheshwarasthan. According to it this place was once surrounded with forests. During cattle grazing they observed that a virgin cow used to sprinkle milk at a particular place. The cattle roamers saw this and began to dig at that place. After digging they got a Shiva linga which began to be worshipped. In course of time a small temple was constructed there.