This settlement is located on the northeastern side of the island stretching along the bays of Loutra, Agia Irini, Schinari, and Maroulas. This is the settlement that most tourists prefer, due to its many restaurants and lodging facilities.
The area is also famous for its hot springs. In fact, this is the reason why Kythnos used to be known as Thermia.
Loutra is the only area of the Cyclades, besides Santorini and its active volcano, where this geothermal phenomenon occurs. The healing waters spring from two different points: the spring of Agioi Anargyroi inside the hydrotherapy centre that has been famous since the 19th century, and the spring of Kakavos, which is only 50m away from there.
The water at Agioi Anargyroi is metallic and hyperosmotic and contains sodium chloride. It has a moderate level of radioactivity and reaches a temperature of 38οC. The water at Kakavos is ferrous, hyperosmotic and hot (52οC), while its level of radioactivity is weak.
The medieval capital of Kythnos, with its famous Castle of Oria or Kefalokastro, was located in the area of Loutra.
It is accessible through a dirt road that later turns into a path. The town was destroyed by the Ottomans in 1570 and has not been inhabited ever since.
* Source: Atlas of Geological Monuments of the Aegean (73,2), published by the Ministry of the Aegean, 2002