once was part of Iwase Province created during the reign of Empress Gensho. The Yoro Ritsuryo established the Iwase Province in 718 through the division of the Michinoku Province (Mutsu Province). It was composed of five districts of Shirakawa (??), Iwase (??), Aizu (??), Asaka (??) and Shinobu (??). The area encompassed by the province reverted to Mutsu some time between 722 and 724.

During the Edo period,