Miyake Subprefecture separated from Ōshima Subprefecture
History
1920: The island halls of Miyakejima and Mikurajima were abolished. Ōshima Island Government Office took control of the islands. The branch office was founded on Miyakejima.
1926: Changed to Ōshima Subprefecture.
1943: Miyakejima Branch Office was split as Miyake Subprefecture.