Orkney Islands, a group of ninety Scotch islands, islets, and skerries, of which only twenty-eight are inhabited, and which have an aggregate area of 376 sq. m., the largest being Pomona or Mainland (207 sq. m.), Hoy (53), Sanday (26), Westray, South Ronaldshay, Rousay, Stronsay, Eday, Shapinshay, Burray, Flotta, &c. They extend 50 miles north-north-eastward, and are separated from Caithness by the Pentland Firth, 6½ miles wide at the narrowest. With the exception only of Hoy (q.v.), which has fine cliffs, and in the Ward Hill attains 1564 feet, the scenery is generally tame, the surface low and treeless, with many fresh-water lochs. The prevailing formation is the Old Red Sandstone, with a small granitic district near Stromness; and the soil is mostly shallow, incumbent on peat or moss. The mean annual temperature is 45°, the rainfall 34.3 inches. The area under cultivation has more than doubled since 1850, but is still less than one-half of the total area. The live-stock during the same period has trebled. The holdings are small—16½ acres on an average; and agriculture and fishing are the principal industries. Kirkwall and Stromness, the only towns, are noticed separately, as also are the standing-stones of Stennis and the tumulus of Maeshowe. Orkney unites with Shetland to return one member to parliament, but it was dissevered therefrom as a county by the Local Government (Scotland) Act, 1889. Pop. (1801) 24,445; (1861) 32,395; (1891) 30,453. The Orkneys (Ptolemy's Orcades) were gradually wrested by Norse rovers from their Pictish inhabitants; and in 875 Harold Haarfager conquered both them and the Hebrides. They continued subject to the Scandinavian crown—under Norse jarls till 1231, and afterwards under the Earls of Angus and Stratherne and the Sinclairs—till in 1468 they were given to James III. of Scotland as a security for the dowry of his wife, Margaret of Denmark. They were never redeemed from this pledge; and in 1590, on James VI.'s marriage with the Danish princess Anne, Denmark formally resigned all claims to the sovereignty of the Orkneys. The present landed proprietors are chiefly of Scotch descent, the islanders generally of mixed Scandinavian and Scotch origin.
See J. R. Tudor's Orkneys and Shetland (1883); and Wallace's Description of the Isles of Orkney (new ed. 1834). For map, see SHETLAND.