The present monograph refers to the administrative organization of the State after Kallikratis. The administrative organization of the State as a legal entity with constitutionally guaranteed powers is structured on the fundamental principle of centralization-decentralization. Within this framework of the administrative organization of the State, there are, on the one hand, the central organs of the State, whose powers extend throughout the territory, and on the other hand, the decentralized state organs that exercise their powers in parts of the territory divided by the legislator based on certain criteria. The work deals with the limits of the legislator in the establishment, organization, and operation of the Local Government Organizations (LGOs) after Kallikratis, in view of Article 102 of the Constitution. The case law of the Council of State on the administrative organization of the State, which has shaped rules by interpreting Article 102 of the Constitution, is examined. These rules constitute the basic framework within which the legislator must move in the reconfiguration of the organizational structure of the LGOs, the powers assigned to them, the transfer of personnel, as well as the obligations of the State for their financial support based on the transferred powers.