Chios is the fifth largest of the Greek islands, situated in the northern Aegean Sea. The island is separated from Turkey by the Chios Strait. Chios is notable for its exports of mastic gum and its nickname is "the Mastic Island". Tourist attractions include its medieval villages and the 11th-century monastery of Nea Moni, a UNESCO World Heritage Site.
Administratively, the island forms a separate municipality within the Chios regional unit, which is part of the North Aegean region. The principal town of the island and seat of the municipality is Chios. Locals refer to Chios town as Chora.
It was also the site of the Chios massacre, in which tens of thousands of Greeks on the island were massacred by Ottoman troops during the Greek War of Independence in 1822.