a historical county of NW Northern Ireland, on the Atlantic: in 1973 replaced for administrative purposes by the districts of Coleraine, Derry, Limavady, and Magherafelt. Area: 2108 sq km (814 sq miles)
2.
a port in N Northern Ireland, second city of Northern Ireland: given to the City of London in 1613 to be colonized by Londoners; besieged by James II's forces (1688–89). Pop: 83 699 (2001)