Interprovincial wars frequently altered its boundaries, notably in 332 when the three Collas, sons of Eochaidh Doimhlein, conquered the land between the river Boyne and Lough Neagh, which became a separate kingdom under the name of Uriel (Oriel or Orgial).
(See Essex, Walter Devereux, 1st earl of.) Sir Brian Mac Phelim's son, Shane Mac Brian O'Neill, Was the last lord of Clanaboy, and from him the family castle of Edenduffcarrick, on the shore of Lough Neagh in Co.
He was, however, induced to take it, and found in his patron's mansion at Portmore, on Lough Neagh, a congenial retreat.
By Lough Neagh, E.
The general surface of the county is gently undulating and pleasantly diversified; but in the northern extremity, on the borders of Lough Neagh, there is a considerable tract of low, marshy land, and the southern border of the county is occupied by a barren range of hills, the highest of which, Slieve Gullion, attains an elevation of 1893 ft.
The Cam or Camlin joins the Bann, which, crossing the north-western corner of the county, falls into Lough Neagh to the east of the Blackwater.
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.
Part of Lough Neagh is in the county, and there are many small loughs, such as Gullion, Cam and Ross.
==Geology== The flat shore of Lough Neagh in the north is due to the thick deposit of pale-coloured clays with lignites, which are probably of Pliocene age, and indicate a reduction of the area of the lake in still later times.
By Lough Neagh, dividing it from the counties Armagh and Tyrone, and by county Londonderry, the boundary with which is the river Bann.
The valleys of the Bann and Lagan, with the intervening shores of Lough Neagh, form the fertile lowlands.
The latter flows to Belfast Lough, the former drains Lough Neagh, which is fed by a number of smaller streams, among them the Crumlin, whose waters have petrifying powers.
The fisheries of the Bann and of Lough Neagh (especially for salmon) are of value both commercially and to sportsmen, the small town of Toome, at the outflow of the river, being the centre.
Lower than Lough Neagh, which it excels in the pleasant scenery of its banks.
Faulting, probably in Pliocene times, lowered the basaltic plateaus to form the basin of Lough Neagh, leaving the eastern scarp at heights ranging up to 1800 ft.
The Lagan Canal connects Lough Neagh with Belfast Lough.
There are three round towers: one at Antrim, one at Armoy, and one on Ram Island in Lough Neagh, only that at Antrim being perfect.