The Shimabara Domain (島原藩), located in Hizen Province, was a ruling domain that held authority over the surrounding area of Shimabara. Originally known as the Hinoe Domain, its administrative center was initially established at Hinoe Castle in Minamishimabara, Nagasaki Prefecture. However, it was later relocated to Shimabara Castle in Shimabara, Nagasaki Prefecture. The domain was governed by various clans, including the Koriki clan of the Tokugawa clan, the Fudaira clan, and the Fukamizo-Matsudaira clan of Juhachi Matsudaira. Additionally, the director of Nagasaki, who held the position of tenryo, and the Ogura Domain, a fudai, also played significant roles as the chief of the tozama daimyo in Kyushu.

Hizen Province was an old province of Japan in the area of the Saga and Nagasaki prefectures. It was sometimes called Hishū (肥州), with Higo Province. Hizen bordered on the provinces of Chikuzen and Chikugo. The province was included in Saikaidō. It did not include the regions of Tsushima and Iki that are now part of modern Nagasaki Prefecture.