Koshi Province is the autonomous easternmost province adopted on 20 September 2015 by Constitution of Nepal. The province is rich in natural resources, tourist attractions, recreational activities, and natural beauty. The province covers an area of 25,905 km2 (10,002 sq mi), about 17.5% of the country's total area. With the industrial city of Biratnagar as its capital, the province includes major eastern towns of Birtamod, Sundar Haraincha, Damak, Dharan, Itahari, Triyuga Municipality and Mechinagar, and the Mount Everest, Kangchenjunga and Ama Dablam. Koshi River, the largest river of the nation, forms the province's western boundary. Under the First-past-the-post voting system issued by the Constituency Delimitation Commission, Nepal, the province hosts 28 parliamentary seats and 56 provincial assembly seats.

Triyuga is one of the eight municipalities of Udayapur district of the Koshi Pradesh of Nepal. Gaighat is the headquarter of the municipality. At the 1991 Nepal census, it had a population of 55,291. The 2011 Nepal census counted 87,557 inhabitants. According to the 2021 Nepal census the total population of the municipality is 102,725. It is divided into 16 wards. Triyuga Municipality was established on B.S. Chaitra 13, 2053. It was named after Triyuga River. A river which flows through the town. Triyuga is the 3rd largest municipality in Nepal and 1st largest in Koshi Pradesh in term of size (area). The total area of the municipality is 547.43 square kilometres (211.36 sq mi)