The largest island of the Orkney Island group, Orkney Mainland (or Pomona) has a length of 26 miles (42 km) from Brough Head in the northwest to Rose Ness in the southeast. Irregular in shape, it lies 16 miles (26 km) north of Duncansby Head on the Scottish Mainland and is surrounded by the islands of the Orkney Islands group. Kirkwall is the principal town of Mainland and lies on the southern shore of the Bay of Kirkwall, an inlet of the Wide Firth on the island's eastern coast. To the south lie the islands of Hoy and South Ronaldsay, separated from Mainland by Scapa Flow, and further south lies the Pentland Firth. Major lochs of the island include the lochs of Stenness and Harray to the west and Broadhound, Hundland and Swannay to the north. The island is covered in prehistoric sites.
The name Pomona - the Roman goddess of fruit - is thought to derive from a mistranslation of a text written by the author Solinus by Latin scholar George Buchanan (1506-82).