- The Sylaun estate in the parish of Belclare, barony of Clare, county Galway, belonged to a branch of the O'Conors of Sligo in the mid 18th century. Following the marriage in 1778 of Thomas Donelan of Peterswell, a member of a junior branch of the Donelans of Ballydonelan, near Loughrea, and Mabel O'Conor, sister and heiress of Thomas O'Conor, Bishop of Achonry, lands belonging to both families came into the possession of their descendants. The O'Conor Donelans were a Catholic landowning family and some later members were involved in the medical profession. Thomas O'Conor Donnellan owned several townlands in the parish of Kilthomas, barony of Loughrea, in 1855 and also held land in the parish and barony of Dunmore. In the 1870s the estate was almost 2,000 acres in size and was mainly located in the parishes of Belclare and Killower.
- An estate of over 3,000 acres in the baronies of Clonmacnowen and Kilconnell, county Galway, was granted to John Donnellan by patent dated 6 Feb 1677/8. Burke states that the Donnellan families of Ballydonnellan, Nutgrove and Hillswood derive from him while the Donnellans of Ballyeighter descend from his younger brother, Richard.
Anthony Donnellan, Ballyeighter and Stephen Donnelan, Killagh, are recorded as resident proprietors in 1824.
The Ballydonnellan estate, the property of Charlotte Donelan, was offered for sale in the Encumbered Estates court in July 1850.
In the 1870s the Donnellan estate at Killagh amounted to over 1100 acres.
For more information on the Donnellan estate see www.ballyd.com.
- This O'Connor family had links with the O'Connor Donelan family of Sylaun, county Galway. In 1796 Valentine O'Connor married Mary, daughter of David Henchy of Rockfield, Blackrock, county Dublin, son of John Henchy of Cratloe, county Clare. Their second son, David, lived at Stonebrook, county Kildare and assumed the additional name of Henchy. At the time of Griffith's Valuation O'Connor Henchy held land in the parish of Graystown, barony of Middlethird, county Tipperary. In 1850 David married Elizabeth, daughter of Sir John Burke, baronet, of Marble Hill, county Galway and in 1887, their son Hugh, married Virginia, only daughter of Andrew Browne of Moyvilla Castle, county Galway. In the 1870s David O'Connor Henchy of Stonebrook, Ballymore Eustace, county Kildare, owned 1,090 acres in county Kildare. Valentine O'Brien O'Connor, the third son of Valentine and Mary O'Connor, lived at Rockfield, county Dublin and also had a residence at Ballykisteen, county Tipperary. In the 1870s he is recorded as owning 837 acres in county Limerick and 78 acres in county Dublin. According to the ''New Zealand Tablet'' (7 Huitanguru [Sept]1874) he bought this property from the Earl of Derby as the newspaper states that an annuity of £5,000 for his wife was charged on the estate under the provisions of his will. He died in September 1873 and was succeeded by his fourth son, William, of Ballykisteen, county Tipperary, who owned 6,178 acres in county Tipperary in the mid 1870s and died childless in 1898.