Okayama Prefecture borders Hyogo Prefecture, Tottori Prefecture and Hiroshima Prefecture.
On March 31, 2005, the town of Hokubo from Jobo District and the towns of Katsuyama, Ochiai, Yubara, and Kuse and the villages of Mikamo, Kawakami, Yatsuka, and Chuka (all from ManiwaDistrict) merged to form the new city of Maniwa.
On March 31, 2005, the town of Katsuta from Katsuta District and the towns of Ohara, Mimasaka, Sakuto, and Aida and the village of Higashiawakura (all from Aida District) merged to form the new city of Mimasaka.