Lord Vishnu, by taking the incarnation of Varaha or Baraha protected the earth from being submerged into Patala (underworld) with his long tusk. Then the Lord sat with his wife Laxmi at the bank of Koshi River and the lap of Himalayas and hills. So, the place bore its name after that event. There is a big and beautiful image of the Baraha incarnation of Lord Vishnu.