Chios is the fifth largest of the Greek islands, situated in the Aegean Sea, seven kilometres (five miles) off the Asia Minor coast. The island is separated from Turkey by the Chios Strait. The island is noted for its strong merchant shipping community, its unique mastic gum and its medieval villages. The eleventh century monastery of “Nea Moni, a UNESCO World Heritage Site, is located on the island.
The capital has also been called "Kastro" or "Kastron" (meaning castle).

Chios island is approximately crescent or kidney shaped, 50 km long from north to south, 29 kLm at its widest, and covers an area of 842 km2 (324 sq. mi). The terrain is principally mountainous and arid, with a ridge of mountains running through the spine of the island. The largest of these, "Pelineon" (1 2 9 6 metres or 4 2 6 0 f t) and "Epos" (1188 metres or 3 9 0 0 f t), are situated in the north of the island. The centre of the island is divided between east and west by a range of smaller peaks, known as "Provatas".

Midway up the east coast lies the main population centres, the main town of Chios and the regions of Vrontados and Kambos. Chios Town, with a population of 32,400, is built around the island's main harbour and medieval castle. The current castle, with a perimeter of 1400 m, was principally constructed during the time of Venetian and Ottoman rule; although remains have been found dating settlements there back to 2000 B.C. The town was substantially damaged by an earthquake in 1881 and only partially retains its original character.
North of Chios Town lies the large suburb of Vrontados (population 4,500), which lays claim as the birthplace of Homer. The suburb lies in the Omiroupoli municipality, and its connection to the poet is supported by an archaeological site known traditionally as "Teacher's Rock" .
Directly south of Chios Town lies the island's airport and the region of Kambos (Κάμπος, "plain"), a large fertile plain noted for its stone mansions and walled orchards. At the southern edge of the Kambos plain lies the town of Thymiana Thymiana is noted as the sole source of a beige-burgundy two-tone sandstone used both in the local mansions and much of the town itself. Inland lie a number of villages rising up into the central mountains culminating with the village of Ayios Georgios Sykoussis perched at the peak dividing east from west. Along the coast lies Karfas (Καρφάς), a large sandy beach, which along with the nearby village of Ayia Ermioni (Άγια Ερμιόνη) is now the main tourist centre with a number of large and small hotels.
The south of the island is noted for the "Mastichochória" literally: Mastic Villages), the 6 villages of Mesta , Pyrgi Olυmpi , Kalamoti , Vessa , and Elata, which together have controlled the production of mastic gum in the area since the Roman period. The villages, built between the 14th and 16th centuries, have a carefully designed layout with fortified gates and narrow streets to protect against the frequent raids by marauding pirates. Between Chios Town and the Mastichoria lie a large number of historic villages including Armolia (Αρμόλια), Myrmighi (Μυρμήγκι), and Kalimassia (Καλλιμασιά). Along the east coast are the fishing villages of Kataraktis (Καταρράκτης) and to the south Nenita (Νένητα).
The south coast is sparsely populated with only two populated areas; the modern bay of Komi and the ancient village of "Emporio", inhabited since 1800 BC, and the site of the black volcanic beach of "Mavra Volia" believed to have been created by the explosion of Santorini island in 1600 BC.

The west coast, between the deep natural harbour of Limenas at the south and the town of Vrontados at the north, forms a crescent shaped series of almost uninhabited rocky bays. The nearest population centres being the two hillside villages of Lithi and Sidirounta, while further inland lie the villages of Elata, Vessa, Avgonyma and the deserted village of Anavatos. On the west coast there still stands a system of stone beacons that were built at regular intervals to signal the approach of ships and warning the islanders against invasions by pirates
The north of the island contains two major villages: Volissos on the west coast, and Kardamyla on the east. Further to the north, are three villages where cherries are grown—Amades, Viki and Kambia.
In June Kambia holds an annual Cherry Festival—"Yiortí ton Kerrasión". Kambia holds several festivals during the summer months. Also located in the northern region is the island's tallest mountain, Mount Pelineon, at 1,297 metres (4,255 ft).
Spartounda and Fyta are a few miles before Kambia. In the village of Fyta stands a watchtower dating back to the late 16th century, the time of the Genoese occupation.
The village of Kourounia lies 20 kilometres (12 mi) north of Volissos in the northwestern part of the island.
Next to Kourounia is the village of Egrigoros

Nea Moni is a monastery with fine mosaics from Constantine IX s reign and a World Heritage Site
Chios' satellite islands include Oinoussais and Psara, from where Kanaris fired the first shots in the Greek War of Independence (1822 onwards).
The Korai Library, in Chios, is one of the most important in Greece, containing 95,000 volumes.
Chios Byzantine Museum
Archaeological Museum of Chios
The town of Vrontados is home to a unique Easter celebration, where competing teams of locals gather at the town's two (rival) churches to fire tens of thousands of homemade rockets at the other church's bell tower while the Easter service is going on inside the churches, in what has become known as rouketopolemos ("the Easter church war").