Kythnos is a Greek island and municipality in the Western Cyclades between Kea and Serifos. It is 56 nautical miles from the harbor of Piraeus. Kythnos is 100 km2 in area and has a coastline of about 100 km. It has more than 70 beaches, many of which are still inaccessible by road. Of particular note is the crescent-shaped isthmus of fine sand at Kolona. There is also a growing coastal settlement called Kanala on the east side of the island, and many of the larger beaches are settled by a handful of residents. Aghios Dimitrios, at the southern tip of the island, is a mostly modern settlement, with small vacation houses dotting the hillside above a wide beach that is dotted with sea daffodils. On the northeast end of the island lies Loutra, a village famous for its thermal springs, which are said to have curative properties. Although the large tourist hotel there has been closed for several years, the bathhouse is still functioning and visitors may soak in its marble tubs for a modest fee.
The port town is called Merichas, its population significantly fluctuating during the year. Many residents of the port speak at least some English, the most popular second language. Merihas is connected to Piraeus and to Lavrion by ferry boat, and the ride takes one to four hours, depending on the speed of the ship and the weather. Construction of a new mole began in 2005 to accommodate larger ferryboats and was completed in 2008. Kythnos was until recently considered to be one of the last Cycladic islands unaffected by the impact of tourism, but this is inexorably changing. Still, the island has not yet been overdeveloped, and in the more remote areas of the villages, traditional ways live on relatively unchanged.