Mahanagni is a village in Majhaulia tehsil in district of Pashchim Champaran, Bihar, India. As per the data provided by Census of India in 2011, total population of Mahanagni was 8,172 which includes 4,226 males and 3,946 females. Mahanagni covers 547 ha area. Pincode of Mahanagni is 845307.