province no. 1 (proposed names: koshi/purbanchal) is the easternmost of the seven provinces established by the new constitution of nepal which was adopted on 20 september 2015. with the industrial city of biratnagar as its headquarter, the province covers other major eastern towns including dharan, itahari and damak while being home to some of the most majestic mountains of the country including the everest, kanchenjunga, and ama dablam. koshi - the largest river of the nation, circumvents the province's western boundary. adhering to the first-past-the-post voting system issued by the constituency delimitation commission, the province hosts 28 parliamentary seats and 56 provincial seats.