Yamagata Castle is a flatland-style Japanese castle located in the center of the city of Yamagata, eastern Yamagata Prefecture, Japan. Throughout the Edo period, Yamagata Castle was the headquarters for the daimyō of Yamagata Domain. The castle was also known as "Ka-jō" (霞城). The castle grounds are protected as a National Historic Site by the Japanese government

Yamagata Domain was a feudal domain in Edo period Japan, located in Dewa Province, Japan. It was centered on Yamagata Castle in what is now the city of Yamagata. Unlike some han whose control was relatively stable throughout the Edo period (1603–1867), Yamagata changed hands a great number of times during its history.