The Municipality of Kea or Tzia belongs to the Cyclades Prefecture of the South Aegean Region and consists of the island of Kea and the island of Makronissos.
The Municipality has an area of ​​148.9km2 and a population of 2.455 inhabitants, based on the latest census of 2011.
The seat of the Municipality of Kea is Ioulida.
The island of Kea or Tzia is the northernmost island of the western Cyclades and the closest to Attica. From Sounio is 12m.
Mythology says that the island was inhabited by the hero Kai, the son of Apollo and the nymph Rodesis.
From the excavations it has been discovered that the first traces of a human settlement date back to the 4th millennium BC. During the 3rd millennium a settlement of the Early Cycladic era was developed in the area of ​​Agia Irini. After 2000 BC there is an influence of the Minoan civilization. In the 12th century BC Kone colonized the Ionians. The island became a member of the AchaeanAthens Alliance. In the following years we encounter pirates on the island and in 1207 it was captured by the Franks, who remained until 1537 and followed by the Turks.
The capital of the island, Ioulida is built in the northern part of the island, amphitheatrically on a hillside and at the top of it lies the castle.
The sights of the island are the ruins of Agia Eirini settlement in Vourkari (10th century BC) and the ruins of two ancient temples in Korissia, where Kouros was exhibited at the Archaeological Museum of Athens. In Poisses there are ruins of temples, towers, cemeteries and inscriptions of Classical and Hellenistic times.
Tzia has very nice beaches with the most famous of Koundouros. The island has a lot of tourism and because it is close to Attica it visits it all year round.

The island of Makronissos was called Eleni because it is believed that the beautiful island of Helen passed through or returning from Troy.
The island in recent years was used as the place of displacement of many Greeks.