- former county of NE Northern Ireland: c. 1,176 sq mi (3,046 sq km)
- district in NE Northern Ireland, in the S part of the former county: 221 sq mi (572 sq km)
- A county in the north-east of Northern Ireland, also known as County Antrim
- The administrative centre of County Antrim
- Glacial gravels are well seen near Antrim town, and as drumlins between Ballymena and Ballycastle.
- It includes the counties Donegal, Londonderry, Antrim, Fermanagh, Tyrone, Ca van, Monaghan, Armagh and Down.
- In 1585 Lord Deputy Sir John Perrot undertook the shiring of Ulster (excluding the counties Antrim and Down, which had already taken shape); and his work, though of little immediate effect owing to the rising of Hugh O'Neill, served as a basis for the division of the territory at the plantation of Ulster in the reign of James I.
- On the death of Domhnall in 911 Niall Glundubh became king of Ailech, and he then attacked and defeated the king of Dalriada at Glarryford, in County Antrim, and the king of Ulidia near Ballymena.
- Shane O'Neill (C. 1530-1567) was a chieftain whose support was worth gaining by the English even during his father's lifetime; but rejecting overtures from the earl of Sussex, the lord deputy, Shane refused to help the English against the Scottish settlers on the coast of Antrim, allying himself instead with the MacDonnells, the most powerful of these immigrants.