Kythnos (Greek: Κύθνος), also known as Thermia, is the second of the Western Cyclades, located between Kea (5 nautical miles) and Serifos. It can only be reached by sea from nearby islands or from mainland ports: Piraeus (52 nautical miles) or Lavrio.
It has an area of 100 km² and about 1600 inhabitants.
Kythnos is mountainous but also has some small cultivated plains. Its highest peak reaches 368 meters (Profitis Ilias). The island's landscape is characterized by the presence of many dry-stone walls.
The inhabitants are engaged in agriculture and fishing, but in the recent past, iron extraction was flourishing.
Its coasts are very jagged, rich in small beautiful beaches, and with truly transparent sea.
The capital of the island is Messaria, and its main port is in Meriha.
The island has the only therapeutic thermal station in the Cyclades at Loutra. Kythnos's craftsmanship includes wicker baskets that are sold throughout the nation. Local products also include cheeses and olive oil. In the past, it was a model city-state, exemplified by Aristotle. Today, it is at the forefront of using alternative energies.
It is a charming and peaceful island, mainly visited by Greeks on vacation due to its proximity to the mainland.
Kythnos is essentially crossed by a single internal road. The coasts are difficult to reach, and several beaches are therefore only accessible by sea. A bus connects the main places on the island, and there is also a modest taxi service.