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.

Biratnagar is a metropolitan city in Nepal, which serves as the capital of Koshi Province. With a Metropolitan Urban Agglomeration population of 244,750 as per the 2021 census, it is the largest city and fastest growing city in the province and also the headquarters of Morang district. As per the preliminary report of 2022 Nepal census, Biratnagar Metropolitan has an estimated city population of 244,750 excluding the suburban areas which are now very well connected to the old town. It is the administrative center of the Greater Birat Development Area which incorporates the cities of Biratnagar and its suburbs and towns of-Itahari-Gothgau-Biratchowk-Dharan primarily located on the Koshi Highway in Eastern Nepal, with an estimated total urban agglomerated population of 804,300 people in 159,332 households including the town of Ithari. Biratnagar is located 399 km (248 mi) east of the capital, Kathmandu, and 6 km (3.7 mi) north of the bordering town of Jogbani in the Indian state of Bihar. It is one of the major entry point in Nepal for Businessmen as well as Tourists who come to visit Nepal for various purposes.