It was centered around Kushizaki Castle and was ruled throughout its history by a cadet branch of the Mōri clan.

Although a vassal of Chōshū Domain, Hideyoshi gave him official recognition as an independent daimyō.

The Kikkawa clan was assigned Iwakuni Domain to protect the eastern approaches, and Mōri Hidemoto was given new territory in Toyoura District, Nagato (now part of Shimonoseki) to guard the west.

The final daimyō of Chōfu, Mōri Mototoshi was granted the kazoku peerage title of viscount (shishaku).

However, as the kazoku peerage guidelines stipulated that former daimyō with kokudaka of between 10,000 and 50,000 koku were to become viscounts, this allegation does not hold water.