West Greece Periphery (Greek: Περιφέρεια Δυτικής Ελλάδος) is one of the thirteen peripheries of Greece. It comprises the western part of Central Greece and the northwestern part of the Peloponnese peninsula. The West Greece Periphery was established in the 1987 administrative reform. With the 2010 Kallikratis plan, its powers and authority were redefined and extended. Along with the Peloponnese Periphery and the Ionian Islands peripheries, it is supervised by the Decentralized Administration of the Peloponnese, Western Greece and the Ionian Islands based at Patras. The periphery is based at Patras and is divided into three peripheral units (pre-Kallikratis prefectures), Aetolia-Acarnania in Central Greece and Achaea and Elis in the Peloponnese, which are further subdivided into 19 municipalities