On October 1, 2004, the towns of Iwami and Mizuho and the village of Hasumi (all from OchiDistrict) merged to form the new town of Oonan.
On November 1, 2004, the towns of Daito, Kamo and Kisuki from OharaDistrict and the towns and villages of Kakeya, Mitoya and Yoshida from IishiDistrict merged to form the new city of Unnan.
On March 31, 2005, the towns of Kashima, Mihonoseki, Shimane, Shinji, Tamayu and Yatsuka and the village of Yakumo (all from YatsukaDistrict) merged with the city of Matsue to form the new city of Matsue.