The fortified area occupied the top of the hill and had a rhomboid ground plan. Its southern and eastern sides were protected by a strong polygonal wall, while the northern side was steep and unwalled. Access to the ancient settlement was via the main gate in the north-east, which was protected by a tower. Inside the citadel the land was formed into successive terraces by strong retaining walls.

After the destruction of Epirus by the Romans in 167 BC, within the fortress an extensive and luxurious residence was constructed, while in modern times in the middle of the lower terrace a small chapel was built, dedicated to St. Donatos. Ancient building material from the superstructure of a significant Hellenistic building was incorporated in its walls.