The ffolliott family held lands in the parish of Aghanagh since the early 18th century. At the time of Griffith's Valuation John Ffolliott was one of the principal lessors in the parish of Aghanagh, barony of Tirerrill. In the 1870s John Ffolliott had over 4000 acres in county Sligo as well as over 1400 in Leitrim and 1700 in Donegal. In 1906 Agnes Ffolliott owned over 600 acres of untenanted land in the barony of Tirerrill. Agnes was one of the five daughters of John Ffolliott. Mary and Margaret eventually inherited the estate. They sold it in the 1920s and went to live in England.
- Survey of leasehold property F.C/D.4/12. Leasehold property held under See of Tuam, 1816. F.C./D.4/16. ; Sligo County Library
- Hollybrook Photographs. 030/060.; Irish Architectural Archive
- Reminiscences of Col. John Ffolliott of Hollybrook, 1824-1894. [Typescript]. ; Sligo County Library
Contemporary printed sources
- LEET, Ambrose. ''A directory to the market towns, villages, gentlemen's seats, and other noted places in Ireland''. Dublin: Printed by B. Smith, 1814 : 218
- PARLIAMENTARY PAPERS. ''Return of owners of land of one acre and upwards, in the several counties .... in Ireland''. HC 1876, LXXX: 304, 321
- 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] : 156
- ORDNANCE SURVEY NAME BOOKS, County Mayo: Vol I, 64
- LEWIS, Samuel. ''A Topographical Dictionary of Ireland''. London: S. Lewis & Co., 1837: Vol I, 93
- LEGG, Marie Louise (ed). ''Census of Elphin 1749''. Dublin: Irish Manuscripts Commission, 2004: Holybrook, 474
- PARLIAMENTARY PAPERS. ''Return of Untenanted Lands in Rural Districts, Distinguishing Demesnes on Which There is a Mansion...'', HC 1906, c, 177: 389.
- McPARLAN, James. ''Statistical Survey of the county of Sligo'' (Dublin: Royal Dublin Society, 1802). : 8-9
- SLATER, Isaac. ''Royal National Directory of Ireland: List of the principal seats''. (Manchester: 1894) : xviii, 31 (Hollybrook)
- BATEMAN, John. ''The great landowners of Great Britain and Ireland''. London: Harrison, 1883. : p.164
Modern printed sources
- BURKE, Sir Bernard. ''A genealogical and heraldic history of the Landed Gentry of Ireland''. London: Harrison & Sons, 1912: 222
- BENCE-JONES, Mark. ''A Guide to Irish Country Houses''. Revised ed. London: Constable, 1988. : 154
- ''Corran Herald'': FAIRBANKS, Catherine. The Ffolliotts of Hollybrook demesne, county Sligo, 1635-1922. XXXV (2002-2003), 20-21.
- McTERNAN, John C. ''Sligo: the light of bygone days, Vol.I Houses of Sligo and associated families''. Sligo: Avena Publications, 2009. : 298-299 (Colgagh), 353-355 (Hollybrook)
- McTERNAN, John C. ''The light of bygone days, Volume II: Sligo families''. Sligo: Avena Publications, 2009. : 100-103