İsahacı is a village in Alaca District, in Çorum Province, Türkiye. İsahacı lies at 939 m above sea level, 9.4 km from the Anatolian plateau mountains. It has 168 inhabitants. The nearest city is Yozgat, 38 km to the south. Among the landmarks around are Hattusa (30 km), Yazılıkaya (29 km) and Alaca Höyük (22 km).