Izushi Domain was a feudal domain under the Tokugawa shogunate of Edo period Japan, located in Tajima Province in what is now the northern portion of modern-day Hyōgo Prefecture. It was centered initially around Izushi Castle in what is now the Izushi neighborhood of the city of Toyooka, Hyōgo.

Tajima Province was a province of Japan in the area of northern Hyōgo Prefecture. Tajima bordered on Tango and Tanba to the east, Harima to the south, and Inaba to the west. Its abbreviated form name was Tanshū (但州). In terms of the Gokishichidō system, Tajimao was one of the provinces of the San'indō circuit. Under the Engishiki classification system, Tajima was ranked as one of the "superior countries" (上国) in terms of importance, and one of the "near countries" (近国) in terms of distance from the capital. The provincial capital was located in what is now the city of Toyooka. The ichinomiya of the province is the Izushi Shrine also located in Toyooka. The area of the province was 2099.01 square kilometers.