The town has a population of 27,015 (2021)[1] and is the administrative capital and main port of both the island and of the regional unit of Chios.

Originally the site of an ancient settlement, the town was first built at the north side of a natural harbour.

By the 16th century, the Byzantine walled town had been further fortified by the Genoese rulers into a massive medieval castle, the "Kastro".

After the devastating earthquake of 1881, the town was substantially rebuilt in neoclassical style, although much of the quayside and outskirts are more modern.

Nevertheless, the centre of the town is still concentrated between the port and castle where the administration, several museums, the main shopping street "Aplotaria", and the municipal gardens lie.