Eday is one of the islands of Orkney, which are located to the north of the Scottish mainland. One of the North Isles, Eday is about from the Orkney Mainland. With an area of , it is the ninth largest island of the archipelago. The bedrock of the island is Old Red Sandstone, which is exposed along the sea-cliffs.
There are various well-preserved Neolithic tombs, as well as evidence of Bronze Age settlement and the remains of a Norse-era castle. During the period of Scottish rule the substantial property of Carrick House was developed at Calfsound, which became a burgh for a short period. During the British era many agricultural improvements were introduced, although there has been a substantial decline in the population since the mid-nineteenth century. In the twenty-first century the Eday Partnership has had success in promoting the island's economy. Local placenames reflect the diverse linguistic heritage and the landscapes of the island and its surrounding seas attract abundant wildlife.