The peripheries (Περιφέρειες) are the official regional administrative divisions of Greece. There are 13 peripheries (nine on the mainland and four island groups), which are further subdivided into 54 prefectures. Traditionally, and also officially until 1987, there were 10 geographical Regions of Greece, which are still sometimes used in popular discourse.
Bordering the periphery of Central Macedonia there is one autonomous region, Mount Athos (Ayion Oros, or "Holy Mountain"), a monastic state under Greek sovereignty. It is located on the easternmost of the three large "fingers" jutting into the Aegean from the Chalcidice peninsula.