Chilwaniyan is a village in Bhitaha tehsil in district of Pashchim Champaran, Bihar, India. As per the data provided by Census of India in 2011, total population of Chilwaniyan was 5,165 which includes 2,705 males and 2,460 females. Chilwaniyan covers 275.6 ha area. Pincode of Chilwaniyan is 845104.