On March 28, 2008, in addition to Sugaya-yakata Castle (Ranzan-machi), already designated as a national historic site, Matsuyama-jo Castle (Musashi Province) (Yoshimi-machi), Ogura-jo Castle (Musashi Province) (Tokigawa-machi, Ranzan-machi, Ogawa-machi) and Sugiyama-jo Castle were designated as national historic sites and all these castles were collectively designated as national historic sites under the name of 'Hiki-jo Castle Ruins.'
2008年（平成20年）3月28日、すでに国の史跡に指定されていた菅谷館（嵐山町）に、松山城(武蔵国)（吉見町）、小倉城(武蔵国)（ときがわ町・嵐山町・小川町）とともに杉山城が追加指定され、「比企城館跡群」の名称で一括して国の史跡に指定された。