Halki is located west and very close to Rhodes. To be exact, it is 36 n.m. from the port of Rhodes, 11 n.m. from Skala Kamirou and only 5 n.m. from cape Armenistis in Monolithos. It is located 230 n.m. away from Piraeus.
With a total extent of 27 sq. km it is one of the smallest islands in the Dodecanese.
Its rocky coasts extend over 40.4 km forming a few beaches with sand and pebbles.
The highest peaks on the island are Merovigli (601m) on its NE part and the hill of Profitis Ilias (579m) in the central part. The terrain is semi-mountainous and infertile due to the earlier systematic overgrazing. Among the elevations there are lowland areas, such as the valleys of Pontami, Lentaki, Kissos and Zia. In the antiquity they had an abundant and renowned production of cereals, a fact that is noted by Theophrastus in his work “Enquiry into Plants”.
Halki has a geographical orientation from East to West. The rocky islets of Nissaki, Agios Theodoros, Atrakoussa, Strongyli, Makri and Alimia, all in the east, are included in its own small island complex.
The only inhabited area on the island is the preserved settlement of Nimborio, built amphitheatrically inside a naturally protected bay on the eastern coast.
The vegetation on the island is Mediterranean maquis consisting mainly of sclerophyllous scrublands and brushwood lands. Notable birds such as Cory's Shearwater, Eleonora's Falcon, Bonelli's Eagle, Phalacrocorax aristotelis and Larus audouinii find shelter on the coastal rocks.