Kos or Cos  is a Greek island in the south Sporades group of the Dodecanese, next to the Gulf of Gökova/Cos. It 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 has both fertile plains and mountainous highlands with a population of 30,947. It comprises three municipalities: Kos, the administrative center and largest town (pop. 17,890), Dikaio, and Irakleides.