Itahari is a sub-metropolitan city located in the Sunsari District of Koshi Province, Nepal. It serves as an important business hub for eastern Nepal and is recognized as one of the fastest-growing cities in the region. According to the 2021 Nepal census, the city has an estimated population of 200,000 people living in 40,207 households.
The city is situated at a strategic junction point where the east-west Mahendra Highway meets the north–south Koshi Highway. Itahari is located approximately 25 kilometres north of Biratnagar, 16 kilometres south of Dharan, and 92 kilometres west of Kakarbhitta. It is the second most populous city in eastern Nepal after Biratnagar.
Itahari is a key component of the Greater Birat Development Area, which includes the cities of Biratnagar, Gothgau, Biratchowk, and Dharan. This urban agglomeration, primarily located along the Koshi Highway, has an estimated total population of 804,300 people living in 159,332 households.