Rivers and hills form natural borders for Udayapur District. The Koshi River to the east separates it from Sunsari District and the Sun Kosi River to the north separates it from Bhojpur and Khotang Di
Triyuga is one of the eight municipalities of Udayapur district of the Koshi Pradesh of Nepal. Gaighat is the headquarter of the municipality. According to the 2021 Nepal census the total population o