Higashisonogi District was established on October 28, 1874 as an administrative division within Sonogi District due to Nagasaki Prefecture enforcing a township law that was passed by the Japanese government. The district comprises today's towns of Hasami, Higashisonogi, Kawatana, parts of Sasebo and the entire city of Omura. The county office was established in Omura (formally known as Omura Town).
In 1902, Sasebo Village was given city status and Sasebo withdrew from the county. In 1942, many towns around Omura merged to become today's Omura City. The city therefore withdrew from the county.[1]
References
^"佐世保市の歴史"(PDF). Sasebo City. Retrieved 15 August 2023.