Hachigata Castle (Hachigata-jō) is a mountain castle, or yamashiro, located in Yorii, Saitama Prefecture, Japan. Hachigata Castle was built in approximately 1476 by Nagao Kageharu of the Late Hōjō clan. The castle was constructed at an excellent location, as it oversaw much traffic at an important crossroads, and was situated between two rivers. Hōjō Ujikuni improved the defences of the castle after he became lord in 1560.
Takeda Shingen attempted to seize the castle in 1568 during the Siege of Hachigata (1568), but failed due to its extensive fortifications. For a month in 1590, Hachigata Castle held off the forces of both Maeda Toshiie and Uesugi Kagekatsu with a mere 3,000 defenders during the Siege of Hachigata (1590). Ujikuni finally surrendered the castle under the condition that the lives of his men would be spared. During the Edo period, the castle was demolished.