In the 18th century Wentworth Thewles of Harristown, Co Kildare, owned lands in counties Mayo, Leitrim and Roscommon. The banking family of La Touche were in possession of much of his estate by the end of the century. In the mid 19th century the representatives of James Thewles held an estate in the parish of Athleague, barony of Killian, county Galway and John E. Thewles held land in the parishes of Kilbride, barony of Ballintober South, Cloonfinlough and Killukin, barony of Roscommon, county Roscommon. The estate of John Edmond Thewles in the baronies of Ballintober South and Roscommon was advertised for sale in the Encumbered Estates' Court in November 1858. In the 1870s Audley C. Thewles of Rugby, England, owned 838 acres in county Roscommon. In the 1870s the representatives of James Thewles held over 2000 acres in county Galway.
- Probate of will (12 Nov 1810) of Major General James Thewles, 8 Jan 1831. Private Sources, Family and Estate Papers 1611-1948. 99/56/1 ; National Archives of Ireland
- Encumbered Estates’ Court Rentals (O’Brien), Thewles, 25 Nov 1858, Vol 54, MRGS 39/027, (microfilm copy in NUIG); National Archives of Ireland
- W.B. Scott, solicitor's collection, includes return of lands & the rents to be set, Wentworth Thewles, 1761. Small Accs. Index 76, D.11,007; National Archives of Ireland
- Map of Ardkeel and Ballybride, barony of Ballintober South for Thewles, 1771. 21 F 43 (27); National Library of Ireland
- Messrs H. & W. Stanley Collection, contains documents re Browne family of Co Mayo & Thewles family of Cos Galway & Roscommon including rentrolls of the Thewles estate, 19th century. M.6236; National Archives of Ireland
Contemporary printed sources
- PARLIAMENTARY PAPERS. ''Return of owners of land of one acre and upwards, in the several counties .... in Ireland''. HC 1876, LXXX: 319
- HUSSEY DE BURGH, U. H. ''The Landowners of Ireland. An alphabetical list of the owners of estates of 500 acres or £500 valuation and upwards in Ireland''. Dublin: Hodges, Foster and Figgis, 1878. [available online at www.askaboutireland.ie] : 442
- PARLIAMENTARY PAPERS. ''Return of names of proprietors and area and valuation of properties in counties in Ireland, held in fee or perpetuity or long leases at chief rents,'' 1876. (412) LXXX. 395: 149.
Modern printed sources
- BENCE-JONES, Mark. ''A Guide to Irish Country Houses''. Revised ed. London: Constable, 1988. : 245
- GLIN, Knight of, GRIFFIN, D. J. & ROBINSON, N.K (eds).'' Vanishing Country Houses of Ireland''. Dublin: Irish Architectural Archive/Irish Georgian Society, 1989. : 78
- MCGINLEY, Michael. ''The La Touche family in Ireland.'' Greystones, county Wicklow: La Touche Committee, 2004.: 39-41