Samastipur is a city and a municipality (nagar parishad) in Bihar, India. It is the headquarters of Samastipur district.It comes under Darbhanga commisenary.The Burhi Gandak River flows through the town.This is one of the five Rail Division of ECR, Hajipur.The Samastipur junction is one of the busiest station in North Bihar after Patna and Katihar.