- The Wyndham/Leconfield Irish estate, derived from the O’Briens, Earls of Thomond, was the largest estate in county Clare containing townlands in seven of the eleven baronies. Colonel George Wyndham was the eldest natural son of George O’Brien Wyndham, 3rd Earl of Egremont, who died in 1837. Following the death of the 4th Earl of Egremont without heirs in 1845 the Colonel succeeded to the Egremont estates which included those of the O’Briens, Earls of Thomond, the remainder of these estates having been left to Percy Wyndham, uncle of George O’Brien Wyndham, 3rd Earl of Egremont, by Henry O'Brien, 8th Earl of Thomond. In 1854 the Wyndham Estate Act was enacted to deal with the limitations of the will of George, 3rd Earl of Egremont, dated 1 January 1841. The Trustees of the Wyndham Estate Act in the 1860s were Lord Naas, Reverend Henry Sockett and Reverend William Sinclair. The rental of their estate in the barony of Tulla Upper amounting to 3,171 acres was advertised for sale in the Landed Estates' Court in April 1861. Further lands in the barony of Islands and houses and premises in Ennis and Limerick were offered for sale in May 1862 and the brewery and premises held by the representatives of Patrick Hickey in March 1863. Colonel George Wyndham was given the title Baron Leconfield in 1859 and died in 1869 when he was succeeded by his son, Henry, 2nd Baron. In the 1870s he owned 37,292 acres in county Clare, 6,269 acres in county Limerick and 273 acres in county Tipperary (parish of Kilmastulla, barony of Owney and Arra). The Wyndham county Limerick estate was located mainly in the parish of Fedamore but also in the parishes of Ballycahane, barony of Smallcounty, Crecora and Monasteranenagh, barony of Pubblebrien, Dromkeen and Grean, barony of Clanwilliam, Grean, Oola, Templebredon and Tuoghcluggin, barony of Coonagh. Thomas Crowe of Ennis was agent for his county Limerick estate. Lord Leconfield lived at Petworth House in Sussex.
- The estate of the Earl of Thomond was the largest in county Clare with lands in seven out of the eleven baronies. In his will dated 14 October 1738 the childless Henry O'Brien, 8th Earl of Thomond, left his estates to the three year old son of his cousin William O'Brien, 4th Earl of Inchiquin, with remainder to his own wife's nephew Percy Wyndham. In 1741 the Earl died and shortly afterwards so did the child to whom he had left his estates. Percy Wyndham became the successor taking the additional surname of O'Brien and in 1756 was created Earl of Thomond. When he died in 1774 without children his nephew George Wyndham, 3rd Earl of Egremont of Petworth House, succeeded to the estates. The unmarried 3rd Earl left his Irish estates to his adopted [natural] son Colonel George Wyndham, created Baron Leconfield in 1859.