The Municipality of Syros-Ermoupolis belongs to the Cyclades Prefecture of the South Aegean Region and includes the islands of Syros, Gyaros and the neighboring islets. The current municipality came from the consolidation of the former municipalities of Ermoupolis, Ano Syros and Poseidon, according to the Kallikratis Program.
The Municipality has an area of ​​101,9 km2 and a population of 21,507 inhabitants, based on the latest census of 2011.
The headquarters of the Municipality of Syros-Ermoupolis is Ermoupolis and the historical seat is Ano Syros.
It is believed that during the Neolithic Age we find residents in Syros. The island was influenced by the Minoans and later by the Mycenaeans. In the 7th century BC, although the islands of the Cyclades began to experience acne, Syros remained from the poor islands. Later, like the other Cycladic islands, he was subjugated to the Persians, and later became a member of the First Alliance of the Athenian Alliance. The conquest was followed by the Macedonians. The island received barbarian raids in the 3rd century BC, resulting in deserting its coastline. In 1204, Syros is subordinated to the Duchy of Naxos. At that time, Ano Syros was inhabited, which, during the Latin occupation, embraced Catholicism while retaining the Greek identity. In 1579 the island was conquered by the Ottomans. The peculiarity exists in the fact that the Catholics of the Ottoman Empire were under the protection of France. Franciscan monks and later Jesuits were installed on the island. During the Revolution of 1821, the Syrians, under the protection of France, maintained a neutral stance and thus its port became a unique refuge in the Aegean. In Syros many refugees from Chios, Kassos, Psara, Crete, Smyrna and the coasts of Asia Minor took refuge.

Ermoupolis, the capital of the island, was a major economic, commercial and naval center in the 19th century. In 1833, the first high school of free Greece was founded, with Neofytos Vamvas being directed by Eleftherios Venizelos, and a few years later he graduated. Also in 1844 the National Bank of Greece inaugurated its first branch in Ermoupolis.
It is one of the cities of Greece that has architectural influences from the West. German and Italian architects worked on the island. The Town Hall is a work of Ernest Tsiller and is one of the largest mayor's mansions in Greece. The Apollo Municipal Theater, a work of the Italian Sampo, is considered a miniature of the Scala of Milan. The Club of Greece, a work of Sambo, was erected in 1862 and served as a venue for world gatherings.
The Philadelphia Theater is a work of 1907 from Pentelic marble. In the harbor area there is one of the oldest buildings, the Clearing House, the work of the German captain and architect Vailer. The Merchant Navy School (1880) housed Ishern's telegraph. Neorio is the largest industrial unit in Syros. These are shipyards and machine shops that have been operating since 1860. The area of ​​Vaporia hosted the most affluent inhabitants and for this the houses are mansions with all-round investment.
In Syros, both Christian churches, Orthodoxy and Catholicism coexist. Indeed, it is one of the few areas in the world with special permission to celebrate Easter on the same date.
Syros has excellent beaches and star hotels. It has been tourism almost all year round because of its short distance from Attica.
Syros is also famous for its loukoumia, which are exported to many parts of the world.