a borough, market, fair, and post town of Ireland, in the county of Londonderry and province of Ulster. It is situated on the east bank of the Lower Bann. Formerly it was a place of great consideration, being the chief town of a county, erected by Sir John Perrot during his government of Ireland; whereas it is now only the head of one of the baronies in the county of Londonderry; but it is still a corporation. It consists of a square called the Diamond, where the market is held. Small streets diverge from each angle of the Diamond, and the general appearance of the place is elegant and respectable. It possesses a church, market-house, several meeting-houses of dissenters, and various genteel residences. The linen trade is carried on extensively; and this is one of the principal markets in Ulster for the sale of that manufacture. A small import trade exists here, the tide coming up to the town, and the river being navigable; but the sea entrance of the bar is difficult and dangerous. The salmon fishery of this place is very productive. It is distant 159 miles north of Dublin. The population amounts to 1530.