Onalvadi is a village in Hosur tehsil in district of Krishnagiri, Tamil Nadu, India. As per the data provided by Census of India in 2011, total population of Onalvadi was 6,656 which includes 3,411 males and 3,245 females. Onalvadi covers 1135.32 ha area. Pincode of Onalvadi is 635109.