Evrytania is almost entirely formed of mountains, including the Tymfristos and the Panaitoliko in the south. Its rivers include the Acheloos in the west, Agrafiotis to the east, and Megdova in the east flowing down to the Ionian Sea. It is one of the least populated regional units in Greece. The area borders Aetolia-Acarnania to the west, southwest and south (west over the Acheloos river), Karditsa regional unit to the north, and Phthiotis to the east. Evrytania also features a famous skiing resort located near Karpenisi on the Tymfristos mountain.