Koshi Province (कोशी प्रदेश) 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, about 17.5% of the country's total area. With the industrial city of Biratnagar as its capital, the province covers other major eastern towns including Birtamod, Birat Chowk, Damak, Dharan, Itahari, Triyuga and Mechinagar and includes several mountains including the Everest, Kangchenjunga, and Ama Dablam. Koshi River, the largest river of the nation, is the province's western boundary. Understanding of 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.
The province is bordered by the Tibet Autonomous Region to the north, the Indian states of Sikkim and West Bengal to the east, Bihar to the south, and Bagmati Province and Madhesh Province to the west. According to the 2021 Nepal census, there are around five million people in the province, with a population density of 190 per square kilometre. In the 2011 Nepal census the province had around 4.5 million people.
Kosi River#Cultural significance
The province is named Koshi after the Koshi River, which is the largest river in the country. On 1 March 2023 the former temporary name of the province, Province No. 1, was changed to Koshi Province. The Kosi river is significantly and culturally an important river of Nepal. The Koshi river is called Kausika in the Rigveda and Kausiki in the Mahabharata. The Kosi is associated with many ancient spiritual stories. It is mentioned in the Bal Kand section of Valmiki's Ramayana as the Kausiki who is the form assumed by Satyavati after her death. In the Markandeya Purana, the Kosi is described as the primal force. Due to the violent nature of the Kosi in monsoon season, legend says that Parvati, the wife of Shiva, after defeating the demon Durg, became known as the warrior goddess Durga who transformed into Kaushiki.