Kos or Cos is a Greek island in the south Sporades group of the Dodecanese, next to the Gulf of Gökova/Cos. The island measures 40 kilometres (25 mi) by 8 kilometres (5.0 mi), and is 4 kilometres (2.5 mi) from the coast of Bodrum, Turkey, and the ancient region of Caria. The island forms a separate municipality within the Kos regional unit, which is part of the South Aegean region. The principal town of the island and seat of the municipality is Kos town. The island has a population of 30,947.