Iwabitsu Castle (Iwabitsu-jō) is a "yamashiro" (castle on a mountaintop) located on Mount Iwabitsu in Higashiagatsuma, Gunma Prefecture, Japan. Iwabitsu Castle was built in the fifteenth century by Azuma Taro Sukefusa of the Takeda clan. It later came under control of the Saitō clan (retainers of the Uesugi clan). The castle once again came under control of the Takeda Clan following a battle. Sanada Yukitaka became lord after this seizure.
The Sanada clan, of whom Yuritaka was a member, retained control of the area after the Takeda Clan (with which the Sanada Clan was at first affiliated) collapsed by changing their loyalty to whichever clan seemed to have the upper hand. In 1615, however, Shōgun Tokugawa Ieyasu declared that each province could have only one castle. As a result, the Sanada Clan dismantled Iwabitsu castle, preferring to instead retain Ueda Castle.