Nijo-jo Castle is located over an area that straddles the southeast corner of what used to be the Greater Imperial Palace of Heiankyo and the Emperor's garden, Shinsen'en, which was to the south of it.
二条城はかつて平安京の大内裏であった場所の南東端とその南にあった禁園（天皇の庭園）である「神泉苑」跡とにまたがる地にある。