In ancient times, Kawa-higashi, including Umaji-cho and Izumo, Chitose-cho on the left side of the Oi-gawa (Hozu-gawa) River, is believed to have been the area where many tumuli were observed and accordingly, large powerful families ruled the area; additionally the provincial monastery was built in the Kokubun area, Chitose-cho.
古代には馬路町・千歳町出雲等の大堰川（保津川）左岸の川東に古墳が多く見られ大豪族がいた地域と見られており、千歳町国分地区に国分寺が置かれいる。