Giriak is a Sub-District (Tehsil/Block/Mandal) in the Nalanda District of Bihar. As par Census 2011 information the sub-district code of Giriak is 01396. There are about 20 sub-districts in Nalanda and Giriak is one of them. Asthawan, Ben, Bihar, Bind, Chandi, Ekangarsarai, Harnaut, Hilsa, Islampur, Karai Parsurai, Katrisarai, Nagar Nausa, Noorsarai, Parbalpur, Rahui, Rajgir, Sarmera, Silao, Tharthari etc. are other sub-districts in Nalanda.There are about 44 villages in Giriak sub-district, which you can browse from villages list.