Kythnos is an island in the Western Cyclades between Kea and Serifos. It is 56 nautical miles (104 km) from the port of Piraeus and 2 hours from the port of Lavrio. It is also called Thermia (the Thermia), at least from the 12th century when the “Diocese of Kea and Thermia” is mentioned. This name is due to the existence of hot springs, which are located in the bay of Loutra.The baths of Kythnos are said to have been enjoyed by both King Otto and Queen Amalia of Oldenburg. According to the 2011 census, the island has a population of 1456 permanent residents. residents respectively.