Viscount Mayo is a title that has been created twice in the Peerage of Ireland, both times for members of the Bourke family. The first creation came in 1627 in favour of Tiobóid na Long Bourke, also known as Theobald Bourke. He was the son of Sir Richard Bourke and Gráinne O'Malley. Miles, the second Viscount was created a Baronet in the Baronetage of Nova Scotia in c. 1638.
His son Theobald, the third Viscount, was also created a Baronet in the Baronetage of Nova Scotia in c. 1638 (although there are no records of this creation in the Great Seal). The third Viscount was executed in 1652 after being found guilty of murder by Cromwell's High Court of Justice in Connaught. The murders in 1642 became known as the "Shrule massacre", but it seems that Lord Mayo had done his best to prevent them.
The third Viscount's daughter Maud married Col. John Browne, ancestor of the Marquesses of Sligo.
On the eighth Viscount's death in 1767, the title became dormant or extinct. Historian Anne Chambers considers that a legal right continued, but that the next claimant could not afford the legal costs involved in presenting a petition to the Irish House of Lords.
Viscounts Mayo; First creation (1627)
- Tiobóid na Long Bourke, 1st Viscount Mayo (died 1629)
- Miles Bourke, 2nd Viscount Mayo (died 1649)
- Theobald Bourke, 3rd Viscount Mayo (died 1652)
- Theobald Bourke, 4th Viscount Mayo (died 1676)
- Miles Bourke, 5th Viscount Mayo (died 1681)
- Theobald Bourke, 6th Viscount Mayo (1681–1741)
- Theobald Bourke, 7th Viscount Mayo (died 1742)
- John Bourke, 8th Viscount Mayo (died 1767)
- Hon. Aylmer Bourke (1743–1748)
Viscounts Mayo; Second creation (1781)
- see Earl of Mayo
- Deposition of Theobald, 3rd viscount, sworn Nov. 1652 (accessed online 17 Oct 2016)
- John Burke's Genealogy, London 1836, see pp. 67–69
- Chambers A, Shadow Lord; Ashfield Press, Dublin 2007