Thasos or Thassos is a Greek island, geographically part of the North Aegean Sea, but administratively part of the Kavala regional unit. It is the northernmost major Greek island, and 12th largest by area. Thasos is also the name of the largest town of the island (officially known as Limenas Thasou, "Port of Thasos"), situated at the northern side, opposite the mainland and about 10 kilometres (6 miles) from Keramoti.