Nisyros is a volcanic Greek island and municipality located in the Aegean Sea. It is part of the Dodecanese group of islands, situated between the islands of Kos and Tilos. Its shape is approximately round, with a diameter of about , and an area of . Several other islets are found in the direct vicinity of Nisyros, the largest of which is Gyali. The Municipality of Nisyros includes Gyalí (pop. 21) as well as uninhabited Pacheiá, Pergoússa, Kandelioússa, Ágios Antónios and Stroggýli. It has a total land area of and a total population of 1,008 inhabitants. The island was also called Nisiro in Italian and Incirli in Turkish.