Kongoukaku (金剛郭) is a stronghold where humans live, protected from Kabane. It is known as the "Shogun's Strongest Stronghold".
Not much is known about Kongoukaku except that it is the most heavily defended station in Hinomoto. As Ikoma notes, a large amount of Kabane research takes place there, and it is also the next destination of Mumei, according to a mission given to her by her older brother. In return for Mumei and Ikoma's actions defending Koutetsujou from the Kabane, Ayame agrees to bring the two to Kongoukaku despite them being Kabaneri.