LON'DONDERRY, a maritime co. of the province of Ulster, in Ireland, 40 rn. length by 34 in breadth, bounded n. by the Atlantic, e. by the county Antrim, and in part by lough Neagh, s. by Tyrone, and w. by Donegal. Its area is 816 sun., or 522,315 acres, of which 91,759 are mountain, bog, waste, water, towns, etc. The pop. in 1871 was 173,906, of whom 77,358 were Catholics, 58,779 Presbyterians, 32,079 Epis copalians, and nearly 1000 Methodists. The surface of Londonderry.is irregular. From the eastern boundary it rises gradually toward the w. for ft distance of about 10 m., where commences an elevated district, rising in several points to a considerable height; Sewell, on the southern border, being 2,236 ft. high. -On the western side the surface falls gradually towards lough Foyle. The coast-line along the Atlantic is gerterally bold and precipitous. The shore of lough Foyle is in most places an unvarying plain. The county may be divided longitudinally into two great geological districts, separated from each other by the river Roe. In the western, which is mountainous, the mica ilate prevails, accompanied in some places by primitive limestone. In the eastern the mica-slate is overlaid by a succession of varying beds, capped, as in the adjacent Antrim district beyond the Bann, by a vast area of basalt, the dip of ye-hick however, is the reverse of that on the opposite side of the river, and increasing in thickness towards the north, where in one place it reaches a depth of 900 feet. Many of the strata contain iron, and the ironstone of the mountain called Slieve Gallion was formerly worked, but the mining operations have been abandoned, from the failure of fuel. The soil is of a very mixed character, the greater part, with the exception of the alluvial spots on the banks of the several rivers, and of a considerable open district which stretches southward to Tyrone, being ill suited for wheat, or indeed for any cereal crop. In the year 1876, 188,926 acres were under crops of all kinds. The number of cattle was 114.376; of sheep, 34,322; of pigs, 38,161. The total value of cattle, sheep, and pigs was £1,594,359. The system of agriculture has been materially improved under the impulse given by the Lon don society upon the large estates which it holds in the county. The principal rivers are the Foyle, the Faughan, the Roe, and the `Bann. The first is navigable as far as Londonderry for ships of 800 tons burden. The Bann, besides being a great source of motive-power for the staple manufacture of Ulster, that of linen, is also celebrated for its salmon-fisheries, which are of great value. The chief towns are Londonderry
city- (q.v.), Coleraine, Newtown-Limavady, and Magherafelt. Londonderry was in ancient times the seat of the great septs of O'Loughlin and O'Neill, and of their tributary sept of O'Calian, or O'Kane. At the immediate period of the invasion the English under John de Courcy attempted a settlement, but were forced by the O'Neills to withdraw. A. small garrison within their colony was established near the Antrim border, at Cole raine, upon the river Bann; but front the 14tb till the 16th c. their tenure was little more than nominal; and although a number of forts, with a considerable garrison, were erected upon the river Foyle in 1600. it was not till the flight of the celebrated Tyrone and O'Donnell that the English occuption of the district was consummated, their forfeited lands being granted by the crown to the corporation of London, who still retain them, the management being vested in a body, 26 in number, who are elected by the conimon council, one half retiring each year. The incorporation, by charter, of this body in 1619 led to the formation of the county, called. from this circumstance, Londonderry. Portions of the county were assigned to the several city companies, the unassigned por. tions being held by the society. Tbe memory of the confiscation long rp.nkled, and perhaps still lingers, in the minds of the dispossessed Irish and their descendants; but in material prosperity the district underwent a rapid and marked improvement. The agriculture is in a condition considerably in advance of the majority of Irish counties, and the domestic manufacture of linen, in former times, added materially to the comfort of the population. Of late years, however, this manufacture, in all its branches, has been transferred for the most part to large establishments. There is considerable export and import trade at the ports of Derry- and Portrush, which is the seaport of Coleraine.
The former has become a port of call for the Canadian steamers, which touch on their outward and homeward passage at the entrance of lough Foyle. The number of national schools in Londonderry in the year 1861 was 386, attended by 20,696 pupils. In 1875 there were 81,488 pupils. Londonderry returns two metnbers to the imperial parliament.