It stretches from the western mountainsides of Parnassus on the east to the mountain range of Vardousia on the west, upon the Gulf of Corinth.

[2] The massive ridge of Parnassus (2,459 m (8,068 ft), which traverses the heart of the country, divides it into two distinct portions.

The neighbouring prefectures are Aetolia-Acarnania to the west, Phthiotis to the north and Boeotia to the east.

Much of the south and east are deforested and rocky and mountainous while the valley runs from Itea up to Amfissa.

Modern Phocis was inhabited by several Greek tribes since antiquity, mainly by Phocians, Locrians and Dorians, which were intermingled and formed the present-day Phocian population, with a unique linguistic and cultural heritage, frequently mentioned as Roumeliotes.

[4] In the summer months, the population nearly doubles due to the influx of tourists.