Kōriyama Castle (郡山城 Kōriyama-jō) was a Japanese castle in what is now the city of Yamatokōriyama, Nara Prefecture, Japan. The Sengoku daimyō Tsutsui Junkei started construction of the castle, and Toyotomi Hidenaga made it his residence.[1] In the Edo period, it became the headquarters of the Kōriyama Domain. During this time it was held by members of the Mizuno, Okudaira Matsudaira, Honda, Fujii Matsudaira, and Yanagisawa clans.