House of O'Brien

Earls of Thomond in the Peerage of Ireland, first creation (1543–1741)

Barons Ibrickane in the Peerage of Ireland (1543–1741)

Earls of Thomond in the Peerage of Ireland, second creation (1551–1741)

Viscount Tadcaster in the Peerage of Great Britain (1714–1741)

Earls of Thomond

• Murrough O'Brien, 1st Earl of Thomond and  1st Baron Inchiquin (died 1551) Earldom for life with a special remainder in favour of his nephew, Donogh O'Brien, the hereditary head of the O'Brien family, and Baron of Inchiquin with the usual remainder to the heirs male of his body.
• Donough O'Brien, 2nd Earl of Thomond, 1st Baron Ibrickane (died 1553) Earldom created with an extended remainder to the heirs male of his body.
• Connor O'Brien, 3rd Earl of Thomond (c. 1535–1581)
• Donogh O'Brien, 4th Earl of Thomond, 4th Baron Ibrickane (died 1624) summoned  to Parliament in 1615 in his father's Barony of Ibrackan.
• Henry O'Brien, 5th Earl of Thomond (c. 1588–1639)
• Barnabas O'Brien, 6th Earl of Thomond (c. 1590–1657)
• Henry O'Brien, 7th Earl of Thomond (c. 1620–1691)
• Henry O'Brien, 8th Earl of Thomond, 1st  Viscount Tadcaster (1688–1741) 

All titles forfeit on his death.

• Charles O'Brien, titular 9th Earl of Thomond, 6th Viscount Clare (1699–1761)
• Charles O'Brien, titular 10th Earl of Thomond, 7th Viscount Clare (1757–1774)

Earl of Thomond in the Peerage of Great Britain (1756–1774)

1st Earl of Thomond

• Percy Wyndham-O'Brien, 1st Earl of Thomond and Baron Ibrickan (c. 1723–1774) younger son of Tory statesman Sir William Wyndham, 3rd Baronet (c.1688-1740) and nephew of 8th Earl of Thomond, the younger son of his wife's sister to whom he left his estates.

Earls of Thomond in the Peerage of Ireland, first creation (1543–1551)

Barons Inchiquin in the Peerage of Ireland (1543)

Earls of Inchiquin in the Peerage of Ireland (1654-1855)

Marquesses of Thomond in the Peerage of Ireland (1800-1855)

Baron Thomond of Taplow in the Peerage of the United Kingdom (1801-1808)

Baron Tadcaster of Tadcaster, in the Peerage of the United Kingdom (1826-1846)

O'Brien of Leaghmenagh in the Baronetage of Ireland (1686, from 1855)

Marquesses of Thomond

• Murrough O'Brien, 1st Earl of Thomond and 1st Baron Inchiquin (died 1551) Earldom for life with a special remainder in favour of his nephew, Donogh O'Brien, the hereditary head of the O'Brien family, and Baron of Inchiquin with the usual remainder to the heirs male of his body.
• Dermod O'Brien, 2nd Baron Inchiquin (died 1 May 1557)
• Murrough McDermot O'Brien, 3rd Baron Inchiquin (1550–1574)
• Murrough O'Brien, 4th Baron Inchiquin (1563–1597)
• Dermod O'Brien, 5th Baron Inchiquin (1594–1624)
• Murrough O'Brien, 1st Earl of Inchiquin, 6th Baron Inchiquin (1618–1674)
• William O'Brien, 2nd Earl of Inchiquin, 7th Baron Inchiquin (1640–1692)
• William O'Brien, 3rd Earl of Inchiquin, 8th Baron Inchiquin (1662–1719)
• William O'Brien, 4th Earl of Inchiquin, 9th Baron Inchiquin (1700–1777)
• Murrough O'Brien, 5th Earl of Inchiquin, 10th Baron Inchiquin (1726–1808)
• Murrough O'Brien, 1st Marquess of Thomond, 5th Earl of Inchiquin, 10th Baron Inchiquin, 1st Baron Thomond of Taplow (1726–1808)
• William O'Brien, 2nd Marquess of Thomond, 11th Baron Inchiquin, 1st Baron Tadcaster of Tadcaster (1765–1846)
• James O'Brien, 3rd Marquess of Thomond, 12th Baron Inchiquin (1768–1855)
• Lucius O'Brien, 13th Baron Inchiquin (1800–1872)
• Edward Donough O'Brien, 14th Baron Inchiquin (1839–1900)
• Lucius William O'Brien, 15th Baron Inchiquin (1864–1929)
• Donough Edward Foster O'Brien, 16th Baron Inchiquin (1897–1968)
• Pádraig Lucius Ambrose O'Brien, 17th Baron Inchiquin (1900–1982)
• Conor Myles John O'Brien, 18th Baron Inchiquin (born 1943)

O'Brien of Leaghmenagh in the Baronetage of Ireland (1686)

 

O'Brien of Leaghmenagh

• Sir Donough O'Brien, 1st Baronet (died 1717) descended from the third son of 1st Earl of Thomond and 1st Baron Inchiquin.
• Sir Edward O'Brien, 2nd Baronet (died 1765)
• Sir Lucius O'Brien, 3rd Baronet (died 1795)
• Sir Edward O'Brien, 4th Baronet (died 1837)
• Sir Lucius O'Brien, 5th Baronet, 13th Baron Inchiquin (1800–1872)

See above

Viscounts Clare in the Peerage of Ireland (1662-1774, attainted 1691)

Earls of Thomond in the Peerage of Ireland, first creation (1543, from 1741-1774 forfeit)

Viscounts Clare

• Daniel O'Brien, 1st Viscount Clare and Baron Moyarta (died c. 1666) younger son of Connor O'Brien, 3rd Earl of Thomond.
• Connor O'Brien, 2nd Viscount Clare (c. 1605 – c. 1670)
• Daniel O'Brien, 3rd Viscount Clare (died c. 1691) attainted in 1691.
• Daniel O'Brien, 4th Viscount Clare (died c. 1693)
• Charles O'Brien, 5th Viscount Clare (died 1706)
• Charles O'Brien, titular 9th Earl of Thomond, 6th Viscount Clare (1699–1761) Marshal of France and Chevalier de L'Ordre du Saint-Esprit.
• Charles O'Brien, titular 10th Earl of Thomond, 7th Viscount Clare (1757–1774)

9th Earl of Thomond, 6th Viscount Clare

Barons Clifton of Leighton Bromswold, in the Peerage of England (1608)

Barons Clifton of Rathmore, in the Peerage of Ireland (1721)

Viscounts Darnley, in the Peerage of Ireland (1723)

Earls of Darnley, in the Peerage of Ireland (1725)

Henry O'Brien, Lord Ibracken, eldest son of Henry O'Brien, 7th Earl of Thomond

• Gervase Clifton, 1st Baron Clifton (d. 1618)
• Katherine Clifton, 2nd Baroness Clifton (c. 1592–1637) married Esmé Stewart, 3rd Duke of Lennox and 1st Earl of March and Baron Stuart of Leighton Bromswold KG (1579–1624).
• James Stewart, 4th Duke of Lennox, 1st Duke of Richmond, 3rd Baron Clifton KG (1612–1655)
• Esmé Stewart, 5th Duke of Lennox, 2nd Duke of Richmond, 4th Baron Clifton (1649–1660)
• Mary Butler nee Stuart, 5th Baroness Clifton (1651–1668) married Richard Butler, 1st Earl of Arran (1639–1686).
• Charles Stewart, 6th Duke of Lennox, 3rd Duke of Richmond,1st Earl of Lichfield and Baron Stuart of Newbury, 6th Baron Clifton, 11th Lord of Aubigny KG (1639–1672)
• Katherine O'Brien nee Stuart, 7th Baroness Clifton (c. 1640–1702) sister of Charles Stewart, 6th Duke of Lennox, 3rd Duke of Richmond. She married Henry O'Brien, Lord Ibracken, eldest son of Henry O'Brien, 7th Earl of Thomond.
• Katherine Hyde, 8th Baroness Clifton (1663–1706) daughter of 7th Baroness Clifton. She married Edward Hyde, Viscount Cornbury later 3rd Earl of Clarendon (1661 – 1723).
• Edward Hyde, 9th Baron Clifton (1691–1713) later styled Viscount Cornbury, predeceased his father and never succeeded as Earl of Clarendon.
• Theodosia Bligh nee Hyde, 10th Baroness Clifton (1695–1722) sister of 9th Baron Clifton. She married John Bligh, 1st Earl of Darnley, 1st Viscount Darnley, and 1st Baron Clifton of Rathmore (1687–1728).
• Edward Bligh, 2nd Earl of Darnley, 11th Baron Clifton of Leighton Bromswold and 2nd Baron Clifton of Rathmore (1715–1747)
• John Bligh, 3rd Earl of Darnley (1719–1781)
• John Bligh, 4th Earl of Darnley (1767–1831)
• Edward Bligh, 5th Earl of Darnley (1795–1835)
• John Stuart Bligh, 6th Earl of Darnley (1827–1896)
• Edward Henry Stuart Bligh, 7th Earl of Darnley (1851–1900)
• Elizabeth Adeline Mary Bligh, 17th Baroness Clifton of Leighton Bromswold (1900-1937)
• Esme Ivo Bligh, 9th Earl of Darnley (1886–1955)
• Peter Stuart Bligh, 10th Earl of Darnley (1915–1980)
• Adam Ivo Stuart Bligh, 11th Earl of Darnley, 20th Baron Clifton of Leighton Bromswold (b. 1941)