TYRONE, an inland county in the province of Ulster, Ireland, is bounded N. by the county of Londonderry, E. by Lough Neagh and the county of Armagh. S. by the ceunties of Monaghan and Fermanagh, W. by the county of Fermanagh, and N.W. by the county of Donegal. It lies within 54° 19' and 54° 57' N. fat., 6° 35' and 7 56' W. long. Its greatest length from oast to west is 60 miles, and from north to south 46 miles. The area, including part of Lough Neagh, is 1,260 square miles, or S06,640 acres, of which 450,296 acres are arable, 311,867 acres uncultivated, 11,991 acres in plantations, 710 acres in towns, and 31,796 acres under water. The population in 1831 was 304,468; in 1841 it was 312,956; in 1851 it was 255,734.
Surface, Ifydrayraphy, and Communications.—This county lies, for the most part, between the two mountainous districts which cross Ulster from east to west. The northernmost of these districts (that of Antrim, Londonderry, and Donegal) encroaches upon the northern border ; and the southernmost (that of Down, Armagh, Monaghan, and Fermanagh) encroaches on the southern border. Outlying groups of mountains occupy portions of the intermediate district. Another group, connecting the two great mountain districts, crosses the county a little to the eastward of the centre, and divides the lower ground, which occupies most of the central and eastern parts of the county, into two parts—the plain or basin of Omagh in the centre, and the plain of Lough Neagh on the east. The diversity of surface renders the county very picturesque, lovely valleys alternating with brawn moorland., and narrow and precipitous gorges with extensive plains.
The plain of Lough Neagh extends south-eastward across tho border of the county, which is here formed by the river Blackwatcr, into the adjacent county of Armagh ; and south-westward to the foot of the mountains which border on the county of Fermanagh: north ward it extends along the shores of Lough Neagh into the county of Londonderry. It is drained by the Ballinderry in the north, and the Blackwater in the south; both have the upper part of their course in the county and the lower part on the border ; the length of the Balliu derry is about 25 miles, of the Blsckwater 46 miles. The Blackwatcr Is navigable for about eight miles, namely, below Charlomont, where the Ulster Canal, which skirts its course on the Armagh side for many miles above the junction, opens into it. A canal, 5 miles long, conveys
the produce of the Coal Islaud collieries into the Black water.
The plain of Omagh is inclosed ou nearly every side by uaouutaius : It extends to the south-west Into the county of Fermanagh, to the border of Lough Erne; and to the north-west to the border of the county of Donegal ; and is drained by the streams which unite to constitute the Foyle.
The Canaan, or Camowen, the principal of the streams which unite to form the Foyle, rises in the mountains that separate the plains of Lough Neagh and Omagh, and flows westward, then northward, to the border of the county at Strabane; and after separating for some miles Tyrone from Donegal, enters the county of Londonderry. Its whole length, including Lough Foyle, Is about 76 miles, of which above fifty miles are in this county or on the border. It is navigable below Nowtonatewart, about thirty miles from its source. The lakes are numerous, but are all small except Lough Neagh, of whose sur face 27,355 acres 1 rood 28 poles, or nearly 43 square miles, are assigned in the Ordnance Survey to this county. Celtenii, Lotion.) Tho Dublin and Londonderry road crosses the county from south east to north-west by Aughuacloy, Omagh, Newtonstewart, and Strabane ; the Armagh and Coleraine road crosses the eastern side of the county, through Mop, Dungannon, and Cookstown. The cross roads are numerous, and are kept in good repair. The Londonderry and Enniskillen railway enters the county near Strabane.
Geology and Mineralogy.—The mountains bordering on Londonderry and Donegal are chiefly of mica-slate interspersed with primitive lime stone ; the chief heights here are Shove Sawel, 2230 feet; Idullagh Clogher, or Straw Mountain, 2093 feet ; and Oughtdoorish, 1906 feet. The mountain group which bouuds:the plain of Omagh on the Deorish is 1119 feet; and north of the plain, MulLagh-carn, 1778 feet ; Ileesy Bell 1390 feet; Slieve Ard, 1381 feet ; and Mary Gray, 820 feet. The hills north-east of the plain of Omagh, between the Owen Killew and the Glenclly, feeders of the Camoan, are of greenstoue, and rise to the height of 1432 feet. There in some granite towards the north-eastern corner of the county. Rocks of old red sandstone and sandstone con glomerate occupy the central district of the county, extending into Fermanagh.