Kyra Panagia (Greek: Κυρά Παναγιά) is a Greekisland in the Sporades. It is administratively part of the municipality of Alonnisos in the Sporades regional unit. The island is also known by the name of Pelagos and rarely Pelagonisi. In Antiquity it was known as Ephthyros (Έφθυρος) and Polyaigos (Πολύαιγος). A bay in the south west of the island is named Agios Petros. Kyra Panagia has belonged to the Athonite monastery of Megisti Lavra since it was granted the island by the Byzantine emperor Nikephoros II Phokas in 963. There is a monastery, currently (2011) under restoration and inhabited by a single monk, on the east coast of the island.
The 1991 census read only one inhabitant making it the smallest municipal district in Greece in population. The tiny settlement became abandoned in the mid to late-1990s. The 2001 census reported a population of ten inhabitants.