Samastipur is a city and a municipal corporation (nagar nigam) in Bihar, India. It is the headquarter of Samastipur district and comes under Darbhanga division. The Budhi Gandak river flows through the town. It is one of the five railway divisions of ECR, Hajipur. Samastipur is a district in Bihar which is spread over an area of 2904 sq. kms. Samastipur is bounded on the north by the Bagmati River which separates it from Darbhanga district. On the west it is bordered by Vaishali and some part of Muzaffarpur district, on the south by the Ganges, while on its east it has Begusarai and some part of Khagaria district. The district headquarters is located at Samastipur.