DONEGAL, a county in the extreme north-west of Ireland, bounded north and west by the Atlantic ocean, east by Lough Foyle and the counties Londonderry and Tyrone, and south by Donegal bay and the counties Fermanagh and Leitrim. The area is 1,193,641 acres. Pop. (1926), 152,511.
The rocks of the county are chiefly igneous or archaean and, structurally, it is a continuation of the Scottish Highlands, the same north-east-south-west structural lines domi nating both, as a result, probably, of post-Silurian ("Caledonian") earth movements. The archaean area usually forms the highest land, with quartzite standing out in white summits at Errigal (2,466 ft.) in the western or Derryveagh mountains, to the south of which is lower land towards Gweebarra bay, mostly formed by igneous rock which stretches north-eastwards along a valley with long lakes, and separates the Derryveagh from the Glendowan mountains, the latter again archaean. An important syncline of carboniferous sandstone and limestone forms the north-east shores of Donegal bay, and another one, or another part of the same one, forms the shores of Lough Foyle in Co. Londonderry and is continued south. Beyond the Donegal bay syncline, to the north-east, is a high igneous mass (Bluestack, 2,219 ft.). Much of the drainage is carried to the Foyle by the Derg and Finn rivers. Donegal includes the high Inishowen peninsula between Lough Swilly and Lough Foyle, formed mainly of archaean rocks (Slieve Snaght, 2,019 ft.), with some carboniferous along Lough Foyle. Lough Swilly is a marked feature ; its upper part is related to the synclinal lines of Donegal bay and runs south-west-north east; its lower part turns out of this direction, and is a feature related to the unequal denudation of igneous and archaean rocks and the general coastal sinking which has contributed so much to the complexity of Donegal's coast-line.
The greater part of Donegal was anciently called Trconnell (q.v.) or the country of Conall; and it was sometimes called O'Donnell's country, after the head chieftains of the dis trict. This district was formed into the county of Donegal in the reign of Queen Elizabeth, in 1585, by the lord-deputy, Sir John Perrott. At the head of Lough Swilly, on the summit of a hill 802 ft. high, are some remains of a fortress or palace of the northern Irish kings. These are known as the Grianan of Aileach, and evidently date from a period prior to the 12th century. On Tory island there are one of the best specimens of a round tower and other remains. Numerous ruins of castles along the coast prove that much attention was formerly paid to the defence of the country from invasion. The principal are Kilbarron castle, near Ballyshannon; Donegal castle and Burt castle. Traces of religious houses, some only in traditionary or documental records, are nu merous; the ruins of that of Donegal, founded in 1474, may still be seen. At Raphoe, 5 m. N.W. of Lifford, is the cathedral of a former diocese united to that of Derry in 1835.
The soil of the greater portion of the county, i.e., the granite, quartz and mica slate districts, is thin and cold, while that on the carboniferous limestone is warm and friable. In most parts of the West the patches of glacial drift form the only agri cultural land. Owing to the boggy nature of the soil, agriculture has not made much progress, although in certain districts (Gwee dore, for instance) much land has been brought under cultivation through the enterprise of the proprietors. Wheat and barley are quite an inconsiderable crop, and in this, as well as in other respects, Donegal is much behind the rest of Ulster. It bears, however, a more favourable comparison as regards its live stock, as cattle, sheep and poultry are extensively kept.
The linen manufacture affords employment to a number of inhabitants, especially at Raphoe, while the manufacture of excel lent homespun, woollen stockings and worked muslin is carried on fairly extensively. The trade in these manufactures and in the domestic produce of the county finds its principal outlets through the port of Londonderry and the inland town of Strabane, Co.
Tyrone. The deep-sea fisheries are important, and are centred at Killybegs, Gweedore and Rathmullen. The salmon fishery is also prosecuted to a considerable extent, the principal seats of the trade being at Ballyshannon and Letterkenny. Bog iron-ore is raised as a gas-purifier ; and talc-schist has been worked for steatite at Crohy Head. The fine-grained sandstone of Mt. Charles, near Donegal, is a well known building stone, and the granites of the north-west have attracted much attention.
Most of the railway lines are owned jointly by the G.N. rail way (Ireland) and the L.M.S. railway, and are controlled by the Co. Donegal joint committee. The chief branch leaves the Great Northern line from Londonderry to Omagh at Strabane. From Stranorlar one line follows the upper Finn valley and serves Glenties, whilst another line utilizes a gap to the south-west and communicates with Donegal. From here local lines serve the fish ing villages and resorts around Donegal bay. Letterkenny is also connected with Strabane by rail. The county town is Lifford, prac tically a suburb of Strabane in Co. Tyrone. Other important towns are Letterkenny (2,308), Ballyshannon (2,112) and Bun crana (2,309) .
The administrative county of Donegal returns eight members to Dail Eireann.
