Orkney, also known as the Orkney Islands, is an archipelago in the Northern Isles of Scotland, United Kingdom, situated off the north coast of Great Britain. Orkney is 16 kilometres (10 mi) north of the coast of Caithness and comprises approximately 70 islands, of which 20 are inhabited. The largest island Mainland is often referred to as "the Mainland". It has an area of 523 square kilometres (202 sq mi), making it the sixth-largest Scottish island and the tenth-largest island in the British Isles. The largest settlement and administrative centre is Kirkwall.