Regional units of Western Greece

Achaea () or Achaia (), sometimes transliterated from Greek as Akhaia (, Akhaḯa, ), is one of the regional units of Greece. It is part of the region of Western Greece and is situated in the northwestern part of the Peloponnese peninsula. The capital is Patras which is the third largest city in Greece.

Aetolia-Acarnania (, Aitoloakarnanía, ) is one of the regional units of Greece. It is part of the geographic region of Central Greece and the administrative region of West Greece. A combination of the historical regions of Aetolia and Acarnania, it is the country's largest regional unit. Its capital is Missolonghi for historical reasons, with its biggest city and economic centre at Agrinio. The area is now connected with the Peloponnese peninsula via the Rio-Antirio Bridge. The surrounding regional units take in Arta in Epirus, a narrow length bordering Karditsa of Thessaly, Evrytania to the n

Elis, also known as Ellis or Ilia (, Eleia), is a historic region in the western part of the Peloponnese peninsula of Greece. It is administered as a regional unit of the modern region of Western Greece. Its capital is Pyrgos. Until 2011 it was Elis Prefecture, covering the same territory.