Iino Domain was created when a 7000 "koku" "hatamoto," Hoshina Masasada was granted an additional 10,000 "koku" of territory in Settsu Province after his appointment as Justicar of Osaka in 1648. On his death, 2000 "koku" was given to his younger son, Hoshina Masafusa, reducing the domain to 15,000 "koku". However, the domain expanded again to 20,000 "koku" under the tenure of Hoshina Masakage. The 10th (and final) "daimyō" of Iino Domain, Hoshina Masaari, served as "wakadoshiyori," and played an important role as a commander in the Second Chōshū expedition. However, during the Boshin War, he switched sides to the Satchō Alliance and was later appointed to judge the guilt of those who had opposed the Meiji Restoration, including many of his relatives from the Hoshina clan of Aizu. Iino Domain became Iino Prefecture on the abolition of the han system in August 1871, and subsequently part of Kisarazu Prefecture, followed by Chiba Prefecture.