- The Thorngates were originally from Gosport in England. Griffith's Valuation shows that James Thorngate and his brothers bought some of the estate of the Blakes of Doonmacreena in the parishes of Crossboyne and Kilvine, barony of Clanmorris, county Mayo and some of the Abbeyknockmoy estate, county Galway of the Blake Forsters. P. Lane writes that the Thorngates also bought portions of the estates of Geoffrey Davies in the barony of Killian and Edmond Concannon in the baronies of Dunmore and Dunkellin. By far their biggest purchase was in 1851 when James Thorngate purchased the Castle Ffrench estate and lived there until the 1860s. The estate was sold, after Thorngate's death, to James Crooke, for whom Daniel Churcher acted as agent. William E. Churcher and George Churcher of Southampton were the trustees of the estate of William Thorngate and much of the Thorngate estate appears to have been in Churcher possession by the 1870s. At the time of Griffith's Valuation James Thorngate is recorded as a land holder in the parish of Rahara, barony of Athlone, county Roscommon.
- Mary Casteleyn's article in ''The Irish Genealogist'' gives a detailed history of this family. Besides their land in county Galway the O'Briens also had land in county Roscommon at Kilmore and Clonboy or Clyboy, parish of Athleague, barony of Athlone. In 1850 James Scott Molloy, assignee of Thomas O'Brien, advertised the sale of the O'Brien estate at Fairfield and Kilmore, amounting to 1439 acres, in the Encumbered Estates' Court. At the time of Griffith's Valuation Kilmore was in the possession of Edward Corcoran and John Sadlier. Dillon O'Brien, a younger brother of Thomas, emigrated to Minnesota, where he became a prominent layman in the Catholic church in America and an author. Marie Adelaide O'Brien, grandmother of Florimond de Basterot was a member of this family. The O'Briens were also related to the O'Connors of Corristoona and Milltown, the Dillons of Dillon's Grove and the Comerfords.