Tsushima Province has been a strategic area that took a major role in the national defense against possible invasions from the continent and in trade with Korea.

After Japan was defeated by Tang dynasty at the Battle of Baekgang in 663, Kaneda Castle was constructed on this island.

It was put in charge of diplomacy and monopolized trade with the Joseon dynasty of Korea.

As a result of the abolition of the han system, the Tsushima Fuchu domain became Izuhara Prefecture in 1871.

In the modern local municipality system, they were divided into Kamiagata and Shimoagata Districts respectively, and were subsequently merged into the city of Tsushima today.