Thandabahiar is a village in Dumri tehsil in district of Giridih, Jharkhand, India. As per the data provided by Census of India in 2011, total population of Thandabahiar was 318 which includes 163 males and 155 females. Thandabahiar covers 120.68 ha area. Pincode of Thandabahiar is 825108.