Onaç is a village in İskilip District, in Çorum Province, Türkiye. Onaç lies at 1,221 m above sea level, in the Geçmiş Dağı mountains. It has 62 inhabitants. The nearest city is Tosya, 41 km to the northwest. Among the landmarks around are İskilip Şeyh Muhiddin Yavsi Mosque (7.5 km) and Great Mosque of İskilip (7.5 km).