Richard Chenevix (bishop)
Richard Chenevix( 1698 – 11 September 1779) was Bishop of Waterford and Lismore.
He was the grandfather of Melesina Trench and was responsible for her upbringing after she was orphaned, until his death.
Lewis Gordon, 3rd Marquess of Huntly
Lewis Gordon, 3rd Marquess of Huntly( c. 1626–1653) was a Scottish nobleman.
He was the third son of George Gordon, 2nd Marquess of Huntly.
Sir Tristram Beresford, 3rd Baronet
Sir Tristram Beresford, 3rd Baronet( 1669 – 16 June 1701) was an Irish politician and baronet.
Michael Isaacs, 3rd Marquess of Reading
Michael Alfred Rufus Isaacs, 3rd Marquess of Reading( 8 March 1916 – 2 July 1980) was an English aristocrat and banker.
Henry Bryant (naturalist)
Henry Bryant( May 12, 1820 – February 2, 1867) was an American physician and naturalist.
He was the grandfather of Henry Bryant Bigelow.
Charles Hope, 3rd Marquess of Linlithgow
Charles William Frederick Hope, 3rd Marquess of Linlithgow MC( 7 April 1912 – 7 April 1987) was a British peer and businessman.
Henry Beresford, 3rd Marquess of Waterford
Henry de La Poer Beresford, 3rd Marquess of Waterford KP (26 April 1811 – 29 March 1859), styled Lord Henry Beresford before 1824 and Earl of Tyrone between 1824 and 1826, was an Irish peer.
He was the second son of the 2nd Marquess of Waterford, but became heir apparent to the marquessate on the death of his elder brother, George Beresford, Earl of Tyrone, in 1824.
He succeeded to the marquessate on his father's death in 1826.
Archibald Kennedy, 3rd Marquess of Ailsa
Archibald Kennedy, 3rd Marquess of Ailsa (1 September 1847 – 9 April 1938) was a Scottish peer
John Beresford, 4th Marquess of Waterford
Reverend John de la Poer Beresford, 4th Marquess of Waterford( 27 April 1814 – 6 November 1866) was an Irish peer and Church of Ireland minister.
Beresford was the third son of the Henry Beresford, 2nd Marquess of Waterford and his wife, Susanna.
He was educated at Eton and Trinity College, Cambridge.
He later entered the ministry and was the incumbent of Mullaghbrack, County Armagh and a Prebendary of St Patrick's Cathedral, serving under his uncle, Lord John.
On 20 February 1843, he married Christiana Leslie, daughter of Charles Powell Leslie II.
They had five sons: Beresford inherited the marquessate from his childless brother in 1859.
On his own death in 1866, the title passed to his eldest son, John.
Henry Beresford, 2nd Marquess of Waterford
Henry de La Poer Beresford, 2nd Marquess of Waterford KP, PC (Ire) (23 May 1772 – 16 July 1826) styled Lord Le Poer from 1783 until 1789 and Earl of Tyrone from 1789 to 1800, was an Irish peer.
Beresford entered the Irish House of Commons for Londonderry County in 1790 and sat for the constituency until the Act of Union.
In 1798, he also stood for Coleraine but chose not to sit.
Beresford became Marquess of Waterford in 1800 after the death of George Beresford, 1st Marquess of Waterford and was appointed a Knight of the Order of St Patrick on 14 March 1806.

Question: Who is Henry Beresford, 3Rd Marquess Of Waterford's paternal grandfather?
Answer: George Beresford, 1st Marquess of Waterford