Northern Islands Province

The Northern Islands Province (北の島州) is the Yamataian province encompassing the Yamataian northern islands, which comprises of the island groups located to the north of the Naichi archipelago. These are the Kitashima islands, Kioshima and Tōishima.

History
Yamatai first settled the Kitashima islands in the 18th century, with northern Yamataian fishermen discovering the large tuna populations in the area and quickly moving to inhabit the islands. The whaling boom of the late 18th century also fuelled further expansion into the islands, and by the early 19th century Kitashima was granted province-level status and separated from Morioka Province as a new Kitashima Province.

In 1867, the Yamataian government officially laid claim to the island of Kioshima, which had been unofficially settled by Yamataian whalers and arctic crabbers for several decades. Due to the lack of government oversight, the island had become a major hotbed of criminal activity. Kioshima was incorporated into Kitashima Province, which was renamed the Northern Islands Province.

Subsequently, Yamatai also attained sovereignty over Tōishima in the 1910s, after which the Yamatai Imperial Navy constructed a small radio base on the island. Uninhabited and barren, the island was used for nuclear testing by the Yamataian nuclear program in the 1970s.

Kitashima islands
The Kitashima island group consists of three large islands and several smaller islands. From north to south, these are Saejima, Shōgaishima, and Kōrishima.

Saejima is the site of the highly secure Batō National Prison, a maximum-security installation operated by the Yamataian Imperial Security Agency to house terrorists and extremely dangerous criminals.

Kioshima
Kioshima is an island roughly 2,720 square kilometres in size. Its largest settlement is Kioshima Town, which has a permanent population of around 54. Kioshima is seasonally inhabited by Yamataian arctic fishermen and whalers, as well as a small amount of tourists. An Air Defence Force radar station is also located on the island.

Tōishima
Located in the Tartaric Ocean, Tōishima is the northernmost point of Yamatai. It is a small island roughly 711 square kilometres, and is largely barren. The only structures on the island are the remnants of military installations used during the Yamataian nuclear tests in the 1970s, as well as an unmanned Yamataian armed forces communications station. The island is a restricted military area and access is forbidden to members of the public without the proper approval.