It includes the counties Donegal, Londonderry, Antrim, Fermanagh, Tyrone, Ca van, Monaghan, Armagh and Down.
The Ulster Canal begins at Charlemont on the river Blackwater, near its junction with Lough Neagh, proceeding through the western border of the county, and passing thence to the south-west by Monaghan and Clones into Upper Lough Erne, after a course of 48 m.
Armagh, together with Louth, Monaghan and some smaller districts, formed part of a territory called Orgial or Urial, which was long subject to the occasional incursions of the Danes.
In August 1539 Manus O'Donnell and Conn O'Neill were defeated with heavy loss by the lord deputy at Lake Bellahoe, in Monaghan, which crippled their power for many years.
Ireland is divided territorially into four provinces and thirtytwo counties: - (a) Ulster (northern division): Counties Antrim, Armagh, Cavan, Donegal, Down, Fermanagh, Londonderry, Monaghan, Tyrone.