The island of Sifnos lies in the Aegean Sea and is a part of the south western Cyclades (situated between Serifos, Kimolos and Paros). It is about 75.6 nautical miles from the Port of Piraeus.

It covers an area of some 73,942 square kilometres, and its coastline is about 705 kilometres long. It is considered to be a medium-sized island. South of the island is the small islet of Kitriani, with its only building, the oldest church of Sifnos, Panagia Kitriani, built sometime between the 10th and 11th century.

The island is traversed by four parallel mountain ranges, the most distinctive peaks being Prophitis Elias (682 m.), in the centre, and Agios Simeon (463 m.) to the north.

According to the last census in 2021, there are 2,777 permanent residents living on the island.

The terrain geomorphology of the island is made up of granite rock formations, clayey sandstone or slate, and limestone, among others. There is also a wealth of mineral deposits, including iron ore, copper, lead, manganese, galena, and magnesium. In ancient times there were gold and silver mines, and the Sifnaion stone quarries, from which the famous fine glass tableware was made, such as the ‘Sifnia’ wine glasses.

The island can be reached by ferryboat throughout the year from Piraeus, Milos, Kimolos, Serifos, Kythnos, Sikinos, Ios, Folegandros, Santorini, Paros and Syros. In summertime the ferry services become more and more frequent and there are additional connections to other destinations, including Mykonos, Naxos and Lavrion. There is also a heliport in the Tholos area of the island, to the north east. The airports nearest to the island are those of Paros, Milos and Syros. The nearest international airports are on the islands of Santorini and Mykonos, but most overseas visitors arrive via the Athens International Airport ‘Eleftherios Venizelos’.