Ilia prefecture is situated in the northwestern part of the Peloponnese peninsula. Its area covers 2,621 square kilometers and the population is 160,110 (2011). Ilia prefecture is part of the region of West Greece along with Aetolia-Acarnania and Achaia prefectures. It is subdivided into 7 municipalities: Pyrgos, Ilida, Andravida- Kyllini, Andritsaina- Krestena, Ancient Olympia, Zacharo and Pineios.
The total area of Ilia prefecture is 2,621 km2, 60% of its soil is mountainous and is crossed by Alfeiós, Pineiós and Erymanthos rivers, and their tributaries. The prefecture is characterized by the existence of coastal wetlands (Kotychi, Kaiafas) which have exceptional natural beauty and ecological wealth. The Ilia plain is the largest in Peloponnese.
Pyrgos, the capital of the prefecture and the largest city of Ilia, is a rapidly booming city, with 48,370 residents. Today's city is built in the same area of the ancient city Dyspontio. Until the 1980s it was called municipality of Lertina (named after the ancient city of Letrina, situated on the outskirts of Pyrgos). The name of the city derived from the tower constructed by the Beis of the wider region, George Tsernotas, in 1512, on the hill of Eparhio, one of the seven hills on which the city was built. This tower was completely destroyed in 1825.