Viscount Mayo of Monycrower in Mayo is in Viscount Ireland.
The London Gazette 12146. 23rd December 1780. Also like Letters Patent, containing His Majesty's Grants of the Dignity of a Viscount of the said Kingdom unto the following Noblemen, and their Heirs Male, by the Names, Stiles and Titles as undermentioned, viz.
James Baron Lifford, His Majesty's Chancellor of Ireland, Viscount Lifford, of Lifford, in the County of Donegall.
Otway Lord Desart, Viscount Desart, of Desert, in the County of Kilkenny.
John Baron Erne [aged 49], Viscount Erne, of Crom Castle, in the County of Fermanagh. [Mary Caroline Hervey Countess Erne [aged 27] by marriage Viscountess Erne of Crom Castle in County Fermanagh.]
Barry Lord Farnham, Viscount Farnham, of Farnham, in the County of Cavan.
Simon Lord Irnham [aged 67], Viscount Carhampton, of Castlehaven, in the County of Cork.
Bernard Lord Bangor [aged 61], Viscoount Bangor, of Castleward, in the County of Downe. [Ann Bligh Viscountess Bangor by marriage Viscountess Bangor of Castleward in County Downe.]
Penyston Lord Melbourne [aged 35], Viscount Melbourne, of Kilmore, in the County of Cavan. [Elizabeth Milbanke Viscountess Melbourne [aged 29] by marriage Viscountess Melbourne of Kilmore in County Cavan.]
James Lord Clifden [aged 46], Viscount Clifden, of Gowran, in the County of Kilkenny.
John Lord Naas [aged 80], Viscount Mayo, of Monecrouer.
On 2nd December 1790 John Bourke 1st Earl Mayo [aged 90] died. His son John [aged 61] succeeded 2nd Earl Mayo, 2nd Viscount Mayo of Monycrower in Mayo, 2nd Baron Naas of Naas in Kildare. Mary Leeson Countess Mayo [aged 56] by marriage Countess Mayo.