The 21th Ephorate of Prehistoric and Classical Antiquitites is located in Athens and includes the perfectures of Cyclades ans Samos.

The authority of the 21th Ephorate of Prehistoric and Classical Antiquities refers to all matters concerning the discovery, safeguard and protection of Hellenic heritage, their exposition in museums, the conservation, reconstruction, study and publication of the monuments as well as the administrative duty to assure the observance of the legislative decrees concerning the antiquities.