The Byzantine castle stands on a low hill at the northern edge of Chios town, overlooking the harbour. Originally built in the Byzantine period, it was substantially enlarged by the Genoese in the 14th and 15th centuries and further modified during Ottoman rule. The walls and towers are largely intact, and the interior of the castle contains a small inhabited neighbourhood — one of the few remaining examples of people still living inside a medieval Greek fortress.
Walking the castle perimeter takes about 30 minutes. The views over the harbour and across to the Turkish coast are excellent. Inside, several of the old buildings have been converted to small museums and galleries; the main gate area has information about the castle's history.
The castle is in the centre of Chios town and easily explored on foot from the waterfront.