I. A county forming the N. E. extremity of Ireland, in the province of Ulster, bounded N. by the Atlantic ocean, E. by the North channel, S. by Belfast Lough and county Down, and W. by Lough Neagh and county Londonderry; area, 1,191 sq. m.; pop. in 1871, 419,782. The surface is hilly, and near the E. and N. E. coasts there are several considerable elevations, from which the country slopes gradually inland to the level of Lough Neagh. There are no considerable rivers except the Bann, which flows between this county and Londonderry. The seacoast is hold and rugged, formed of lofty basaltic cliffs, and presenting, between Bengore Head and the mouth of the Bann, the singular formation known as the Giant's Causeway. (See Giant's Causeway.) In the N. E. part of the county, called "the Glens," are picturesque and fertile valleys, and the scenery is varied and pleasing. Besides agriculture, the linen manufacture is the chief employment of the people; and along the coasts an extensive fishery is carried on.

The principal towns are Belfast, the county town (a part of which, however, belongs to county Down), Antrim, Ballymena, Carrickfergus, Larne, and Lisburn.

II. A market town of the preceding county, situated on the right bank of the Six-Mile Water, less than a mile from its embouchure into Lough Neagh, and 13 m. N. W. of Belfast; pop. in 1871, 2,131. It is a principal seat of the linen manufacture. The town is well built, and consists of little more than one long street, with its short cross streets. Near it are Antrim castle and Shane's castle, one of the celebrated round towers of Ireland. On June 7, 1798, a battle was fought here between the English troops and the United Irishmen, resulting in a victory for the former.