Kyūshū is the third-largest island of Japan's four main islands and the most southerly of the four largest islands. In the past, it has been known as Kyūkoku , Chinzei and Tsukushi-no-shima . The historical regional name Saikaidō referred to Kyushu and its surrounding islands. Kyushu has a land area of 36,782 square kilometres (14,202 sq mi) and a population of 14,311,224 in 2018.

Chikugo Province was a province of Japan in the area of northern Kyūshū, corresponding to part of southwestern Fukuoka Prefecture. Chikugo bordered on Higo and Chikugo to the southeast, and Chikuzen to the north and east, Bungo to the east and Hizen to the west. Its abbreviated form name was Chikushū (筑州), although it was also called Chikuin (筑陰). In terms of the Gokishichidō system, Chikugo was one of the provinces of the Saikaidō circuit. Under the Engishiki classification system, Chikugo was ranked as one of the "superior countries" (上国) in terms of importance, and one of the "far countries" (遠国) in terms of distance from the capital.