It includes the counties Donegal, Londonderry, Antrim, Fermanagh, Tyrone, Ca van, Monaghan, Armagh and Down.
The Sligo, Leitrim & Northern Counties railway connects with the Great Northern at Enniskillen, and the Clogher Valley light railway connects southern county Tyrone with the Great Northern at Maguiresbridge.
Aedh (Hugh) O'Neill, chief of the Cinel Eoghain, or lord of Tir-Eoghain (Tir-Owen, Tyrone) at the end of the 12th century, was the first of the family to be brought prominently into conflict with the Anglo-Norman monarchy, whose pretensions he took the lead in disputing in Ulster.
Conn O'Neill (c. 1480-1559), 1st earl of Tyrone, surnamed Bacach (the Lame), grandson of Henry O'Neill mentioned above, was the first of the O'Neills whom the attempts of the English in the 16th century to subjugate Ireland brought to the front as leaders of the native Irish.
Conn, who was related through his mother with the earl of Kildare (Fitzgerald), became chief of the Tyrone branch of the O'Neills (Cinel Eoghain) about 1520.