Ios is an island in the Cyclades group in the Aegean Sea.
Ios is a hilly island with cliffs down to the sea on most sides, situated halfway between Naxos and Santorini. The Port of Ios is at the head of the Ormos harbor in the northwest. From there the bus or 15-minute walk up the steep donkey path takes you to the village, known as Chora. This is a white and very picturesque cycladic village, full of stairs and narrow walks, that makes it inaccessible for cars of any kind.
The north end of Ios also has a ruined Venetian castle from the 15th century. The island is said to have 365 churches and chapels, like the days of the year.
Ios attracts very large numbers of young tourists, many of whom used to sleep on their sleeping bags during the 1970s on the popular beach of Milopotamos (or Milopotas) after partying through the night. Today Milopotamos beach has been developed to an equivalent mass package tourism resort like Platys Gialos and Paradise Beach of Mykonos.