Koir Ganwan is a village in Kalyanpur tehsil in district of Purba Champaran, Bihar, India. As per the data provided by Census of India in 2011, total population of Koir Ganwan was 1,322 which includes 665 males and 657 females. Koir Ganwan covers 195 ha area. Pincode of Koir Ganwan is N/A.