The butterfly-shaped Astypalaia lies between the Cycladic and Dodecanese island clusters and although administratively belongs to the latter, geographically and architecturally is more akin to Cyclades.
It covers an area of 96,42 km2 and has a population of 1.238 that is dispersed into four settlements (Chora, Analipsi, Livadi, Vathi). The main settlement of Astypalea consists of Pera Gialos port and the picturesque hill-top village of Chora, crowned by an imposing 15th century Venetian castle. Within the walls of the castle lie two 14th century churches, Evangelismos and Agios Georgios, while the patron saint of the island, Virgin Mary Portaetissa, stands just outside the southwest wall.
Astypalea municipality belongs to the eparchy of Kalymnos island.