This is a branch of the royal house of STUART, springing from Robert, Duke of Albany, third son of ROBERT II of Scotland.
ANDREW STEWART, 1st Lord Avondale, was the natural son of JAMES THE FAT (sole surviving son of Murdoch Stewart, 1st Duke of Albany).
He wedded Margaret, sister of David, 1st Earl of Cassillis, and had issue,
ANDREW, his successor;His lordship fell at the battle of Flodden, in 1513, and was succeeded by his eldest son,
Henry, 1st Lord Methven;
Barbara; Agnes; Anne.
ANDREW (c1505-49) succeeded his uncle as 2nd Lord Avondale, who exchanged the title for that of OCHILTREE.
He married Margaret, natural daughter of James, 1st Earl of Arran, and had issue,
ANDREW, his successor;This nobleman was succeeded by his eldest son,
ANDREW (c1521-91), 2nd Lord Ochiltree, who married Agnes Cunningham, and had a son and heir, Andrew Stewart, styled Master of Ochiltree, who predeceased him in 1578, and was succeeded by his grandson,
ANDREW, 3rd Lord Ochiltree (c1560-1629), who, having thus divested himself of that title, was created a peer, in 1619, by the title of Baron Castle Stewart.
He wedded, ca 1587, Margaret, daughter of Sir John Kennedy, of Blairquhan, and had issue,
ANDREW, his successor;His lordship was succeeded by his eldest son,
JOHN, 5th Baron;
Robert, ancestor of the Earl Castle Stewart;
Margaret, m George Crawford, of Crawfordsburn;
Maria, m John Kennedy, of Cultra;
ANDREW, 2nd Baron, who espoused, ca 1604, Lady Anne Stewart, fifth daughter and co-heiress of John, 5th Earl of Atholl, by which lady he had issue,
ANDREW, 3rd Baron;His lordship was succeeded by his eldest son,
JOSIAS, 4th Baron.
ANDREW, 3rd Baron (-1650), who married Joyce, daughter and heiress of Sir Arthur Blundell, by whom he had issue, an only child, MARY, who wedded Henry 5th Earl of Suffolk.
His lordship died without male issue, and the honours devolved upon his brother,
JOSIAS, 4th Baron (c1637-62), who espoused Anne, daughter of John Madden, of Enfield, Middlesex, by his wife Elizabeth, daughter and co-heiress of Charles Waterhouse, of Manor Waterhouse, County Fermanagh.
This marriage was without issue and the family honours reverted to his lordship's uncle,
JOHN, 5th Baron, after whose decease without issue, the title remained in abeyance until 1774, when it was claimed by, and allowed to,
CAPTAIN ROBERT STEWART, de jure 6th Baron, who married Anne, daughter of William Moore, of Garvey, County Tyrone.
He died ca 1685, and was succeeded by his son,
ANDREW, de jure 7th Baron (1672-1715), who wedded Eleanor, daughter of Robert Dallway, of Bellahill, County Antrim, by whom he had issue,
ROBERT, de jure 8th Baron (1700-42), who wedded, in 1722, Margaret, sister and co-heiress of Hugh Edwards, of Castle Gore, County Tyrone, and had issue,
ANDREW THOMAS, 9th Baron (1725-1809), who was created Viscount Castle Stewart in 1793; and advanced to an earldom, as EARL CASTLE STEWART, in 1800.
His lordship wedded, in 1781, Sarah, daughter of the Rt Hon Godfrey Lill, judge of the Court of Common Pleas in Ireland, by whom he had issue,
ROBERT, his heir;
ROBERT, 2nd Earl (1784-1854), who espoused, in 1806, Jemima, only daughter of Colonel Robinson, by whom he had issue,
EDWARD, 3rd Earl;
CHARLES ANDREW KNOX, 4th Earl;
Andrew Godfrey, in holy orders, father of 6th Earl.
EDWARD, 3rd Earl (1807-57), who married, in 1830, Emmeline, only surviving daughter and heir of Benjamin Bathurst, in a childless marriage.
His lordship was succeeded by his brother,
CHARLES ANDREW KNOX, 4th Earl (1810-74), who wedded, in 1835, Charlotte Raffles Drury, only daughter of Acheson Quintin Thompson, of County Louth, and had issue,
HENRY JAMES, his heir;
Mary; Ella Sophia; Alice Maude; Margaretta.
HENRY JAMES, 5th Earl,
- Henry James Stuart-Richardson, 5th Earl (1837–1914);
- Andrew John Stuart, 6th Earl (1841–1921);
- Arthur Stuart, 7th Earl (1889–1961);
- Arthur Patrick Avondale Stuart, 8th Earl (b 1928).
The heir apparent is the present holder's son, Andrew Richard Charles Stuart, styled Viscount Stuart (b 1953).