LETTERKENNY, a market-town and post-town, in the parish of CONWALL, barony of KILMACRENAN, county of DONEGAL, and province of ULSTER, 13 miles (W.) from Lifford, and 118 (N. W.) from Dublin, on the road from Lifford to Ramelton and Dunfanaghy; containing 2160 inhabitants. It is situated on the river Swilly, over which is a bridge of one arch, and consists of one street with a spacious market-square, containing 416 houses. The market is on Friday, and is well supplied with provisions; the fairs are on the first Friday in January, May 12th, July 10th, the third Friday in August, and Nov. 8th. A constabulary police force is stationed here; petty sessions are held every Wednesday, and the quarter sessions for the county are held here in April and October; the court-house is a neat building, and there is a bridewell, containing six cells and two day-rooms, with two airing-yards. In the mountains in the vicinity are great quantities of stone of good quality, and marl; about half a mile from the town, and about the same distance from Lough Swilly, is a good quarry of slate; and on the shores of the lough are great quantities of potters' clay and clay for bricks. The river is navigable from Lough Swilly to this place for vessels of 150 tons' burden. The parish church, and the R. C. chapel of the district of Aughnish, a plain small building, are situated in the town; and there are three places of worship for Presbyterians respectively of the Ulster and Seceding Synods and for Covenanters. There are also a national school, a dispensary, and a small fever hospital. Near this place were the ancient English settlements of Drummore and Lurgagh, comprising about 2000 acres, with a bawn of brick and a castle of stone in a strong position, also a village at some distance, in which were 29 British families able to muster 64 men-at-arms; and Dunboy, a territory comprising 1000 acres, where, at the time of Pynnar's survey, in 1619, Mr. John Cunningham had a strong bawn, 70 feet square and 14 feet high, defended with two lofty towers, with a castle and 26 houses and a mill within the enclosure, the houses tenanted by British families, able to muster 50 armed men.