Chios (Greek: Χίος, alternative transliterations Khios and Hios, Scio, Khora, Khóra, Sakiz, Castro and Kastron, see also List of traditional Greek place names; Ottoman Turkish: صاقيز Sakız; Genoese: Scio; Italian: Chio) is a Greek island in the Aegean Sea seven kilometres (five miles) off the Turkish coast. Chios is the location of the monastery of Nea Moni, an UNESCO World Heritage Site.

Chios island's main town and administrative centre is also called Chios although it is often referred locally as Chora ("The Town").

Politically, Chios is also a prefecture of Greece within the North Aegean periphery. Chios prefecture covers the islands of Chios, Psara and Oinousses, and provides two representatives to the Greek parliament.

The island is approximately crescent shaped, 50km long from north to south, 29km wide at the north, and covers an area of 904 km² (350 sq. miles). The terrain is principally mountainous and arid, with a ridge of mountains running through the spine of the island. The largest of these, "Pelyneon Oros" (1297 metres or 4260 feet) and "Oros" (1188 metres or 3900 feet), lie in the north while the centre of the island is divided between east and west by a range of smaller peaks.

Chios has a resident population of approximately 52,290 (2001 census). As well as the large number of islanders living in Athens, the island has a considerable Diaspora abroad, notably in London and New York. The island is famous for its medieval villages, its scenery and good climate. Its chief export is mastic but it also produces olives, figs, and wine. Its international fame is based on the size and quality of its shipping community.

Midway up the east coast lies the main population centres, the main town of Chios and the suburbs of Vrondathos and Kambos. Chios town is built around the island's main harbour and medieval castle. The castle, with a perimeter of 1400m, dates mainly from the Venetian and Ottoman times; although remains have been found dating the settlement back to 2000 B.C. The town was substantially damaged by an earthquake in 1957 and only partially retains its original character. South of the town lies the island's airport and the region of Kambos, a large fertile plain noted for its stone mansions and walled orchards. Further along the coast, Karfas, originally a large sandy beach, is now the main tourist centre with a number of large and small hotels.

The south of the island is noted for the "Mastichochoria", the six villages of Kalamoti, Mesta, Vessa, Pyrghi, Olympi and Elata, which together controlled the production of Mastic gum in the area. The villages, built between the 14th and 16th centuries, are substantially fortified to protect against the frequent raids by marauding pirates. Also of note is the village of "Emporio" at the southern tip of the island and the neighbouring black volcanic beach of "Mavra Volia".

The west coast, consisting of a series of rock bays is only lightly inhabited. Of note, is the system of stone beacons running along the coast to signal the approach of pirates.

The north of the island contains two substantial towns: Volissos on the west coast, and Kardamyla on the east. There are three villages to the North of the Island that are renowned for growing Cherries, the only three villiages on the island that grow cherries, Amades, Viki and Kampia

In the interior lie the 11th century monastry of Nea Moni and the deserted village of Anavatos, both sites of famous massacres during the 1822 rebellion.

• Nea Moni is a monastery with fine mosaics from Constantine IX's reign and a World Heritage Site.

The costumes and the scenery are entirely authentic. This and the works of Lord Byron did much to draw the attention of mainland Europe to the catastrophe that had taken place on Chios (1824, oil on canvas, 419 x 354 cm, Musée du Louvre, Paris

• Chios claims to be the birthplace of Homer, Hippocrates the mathematician, and Oenopides. Oenopion, a legendary king, is said to have brought winemaking to the island.

• Chios is home to one of the biggest ship-owning fraternities in Greece, with such shipping families as Livanos, Chandris, Los, Lemos, Pachos, Pateras, Fafalios, Frangos, Pittas, Caroussis and Xylas hailing from the island.

• Chios' satellite islands include Oinoussais and Psara, from where Kanaris fired the first shots in the Greek War of Independence (1822 onwards).

• Some claim Chios is Christopher Columbus's birthplace. Columbus said he was from the Republic of Genoa, but he never claimed he was from the city of Genoa itself. Chios was a Genoese possession at the time of Columbus birth, and 'Columbus' is a common surname on Chios. Furthermore Columbus appears to have known Chios very well, since he often made references to it in his journals[citation needed].

• Chios is also the birthplace of some well known poets of modern times as Giorgos Dilvois, Nikos Gialouris, Dimitris Varos and Matheos Moundes.

• The Korai Library, in Chios, is one of the most important in Greece, containing 95,000 volumes.

• Chios Museum of Byzantine and Post-Byzantine Art, Website

• Chios Archaeological Museum, Website

• 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").

• Chios is the birthplace of 19th century Ottoman grand vizier İbrahim Ethem Pasha who also had notable descendants (carrying the surname "Eldem" to this day), the most notable among these being the painter Osman Hamdi Bey.

• Namık Kemal, one of the principal pillars of the foundation of modern Turkish literature, served as a sub-prefect (exiled in practical terms) in Chios