Earl Mountnorris of Mountnorris Castle in Armagh is in Earl Ireland.
On 14th February 1761 Richard Annesley 6th Earl Anglesey [aged 68] died. Earl Anglesey and Baron Annesley Newport Pagnell Buckinghamshire extinct. His succeeded son Arthur [aged 16] succeeded 8th Viscount Valentia, 6th Baron Altham.
Arthur Annesley 1st Earl Mountnorris didn't succeed as 7th Earl Anglesey since his parent's secret marriage in September 1741 was not supported by sufficient evidence for the English House of Lords to accept his legitimacy. He was subsequently created Earl Mountnorris of Mountnorris Castle in Armagh more or less in compensation.
He succeeded to the Irish titles Viscount Valentia and Baron Altham since the Irish House of Lords did believe his legitimacy.
On 3rd September 1790 George Annesley 2nd Earl Mountnorris [aged 19] and Anne Courtenay Countess Mountnorris [aged 16] were married. Anne Courtenay Countess Mountnorris by marriage Countess Mountnorris of Mountnorris Castle in Armagh. She the daughter of William Courtenay 8th Earl Devon and Frances Clack Countess Devon. He the son of Arthur Annesley 1st Earl Mountnorris [aged 46] and Lucy Lyttelton Baronet.
On 3rd December 1793 Arthur Annesley 1st Earl Mountnorris [aged 49] was created 1st Earl Mountnorris of Mountnorris Castle in Armagh. Sarah Cavendish Countess Mountnorris by marriage Countess Mountnorris of Mountnorris Castle in Armagh.
The London Gazette 13609. From Tuesday 31st December 1793 to Saturday 4th January 1794.
To the Right Honorable Arthur Viscount Valentia [aged 49], and the Heirs Male of his Body lawfully begotten, the Dignity of Earl Mountnorris, of Mountnorris Castle, in the County of Armagh.
To the Right Honorable Andrew Thomas Lord Castlestewart [aged 68], and the Heirs Male of his Body lawfully begotten, the Dignity of Viscount Castlestewart, in the County of Tyrone.
On 4th July 1816 Arthur Annesley 1st Earl Mountnorris [aged 71] died. His succeeded son George Annesley 2nd Earl Mountnorris [aged 45] succeeded 2nd Earl Mountnorris of Mountnorris Castle in Armagh, 9th Viscount Valentia, 7th Baron Altham.
On 23rd July 1844 George Annesley 2nd Earl Mountnorris [aged 73] died. Earl Mountnorris of Mountnorris Castle in Armagh and Baron Altham extinct. His succeeded half fourth cousin once removed Arthur Annesley 10th Viscount Valentia [aged 58] succeeded 10th Viscount Valentia.