Caithness, a county in the extreme NE. of the Scottish mainland. Its length from NE. to SW. is 43 miles; its greatest breadth, 28 miles; and its area, 701 sq. m. Except in the west and south, where the mountain-range dividing Caithness from Sutherland attains in Morven a height of 2313 feet, the general aspect of Caithness is level and bare, being in great part moorland and treeless. The northern sea-coast is bold and rocky, with many bays, inlets, promontories, and caves. Here are Dunnet Head and Duncansby Head; and on the west side of the last-named is John o' Groat's House (q.v.). There are no navigable rivers in Caithness, and no lakes of importance. The climate is damp and chilly, but snow rarely lies on the plains above a day or two at a time. Thunder is rare; auroras are seen almost nightly in winter. Coal has not been found in Caithness; the common fuel is peat. The chief crops are oats, bere, turnips, and potatoes; but only 23 per cent. of the entire area is in cultivation. The parts which are under tillage are generally a deep fertile loam on a strong till clay. In the north-east the soil is sandy. The crops are 20 days later in ripening than in the Lothians. The occupants of many of the small farms divide their time between farming and fishing.
There are herring, ling, cod, salmon, and lobster fisheries. The herring-fishery falls in the months July and August, and Wick is a chief seat of the British herring-fishery. The other exports are cattle, oats, wool, and flagstones, of which, as well as of freestone and slate, Caithness contains quarries, the chief being that of Castlehills, 5 miles to the east of Thurso. The county returns one member to parliament; and Wick is its only parliamentary burgh; another town is Thurso, an old burgh of barony. A railway, completed in 1874, and extending to Wick and Thurso, connects Caithness with the south. Pop. (1801) 22,609; (1861) 41,111; (1881) 38,865; (1891) 37,177. In early times Caithness is supposed to have been inhabited by Celts, who afterwards mixed with Danes and Norwegians; and from the 10th century to 1196 it was subject to Scandinavian jarls. The Scandinavian origin or part-origin of the people of Caithness is shown by their tall forms and fair features, and their speaking English instead of Gaelic. Caithness has remains of brochs or Picts' houses, stone-circles, and several old castles. See Laing's Prehistoric Remains of Caithness (1866), Calder's History of Caithness (new ed. 1887).
CAITHNESS FLAGSTONES are thin-bedded dark-coloured bituminous sandstones, slightly micaceous and calcareous, valuable on account of their great toughness and durability for pavements, cisterns, and various other purposes, and accordingly are largely exported. They belong to the Old Red Sandstone (q.v.), and contain abundant remains of fossil fishes.