The MacDermots were the original hereditary owners of the lands in Coolavin, hence the family title MacDermot of Coolavin. In the 17th century they lost much of their lands but always maintained a presence in the area. In the early 19th century they held a house and demesne at Coolavin. McParlan recorded "Doctor McDermott, son and heir of the late Prince of Coolavin, ........resides in the family mansion". At the time of Griffith's Valuation, Charles McDermott was the lessor of most of the townland of Monasteraden, barony of Coolavin and was also leasing lands in the barony of Tirerill. Portion of this property, including the house and demesne at Coolavin, was offered for sale in the Encumbered Estates Court in 1852. Lands in the barony of Tirerrill were offered for sale in March 1860. In the 1870s Charles J. McDermott owned almost 800 acres in county Sligo while Roderick and Thomas McDermott owned another 800.
- Encumbered Estates' Court Rentals (O'Brien), McDermott, 5 November 1852, Vol 18, MRGS 39/008 (microfilm copy in NUIG) ; National Archives of Ireland
- Coolavin photographs & press cuttings, 030/059.; Irish Architectural Archive
- Landed Estates' Court Rentals (O'Brien), McDermott, 13 March 1860, Vol 58 MRGS 39/029, (microfilm copy in NUIG; National Archives of Ireland
- MacDermot of Coolavin papers. c.1595-1790. [Microfilm copy of some of these papers P.7079]; National Library of Ireland
Contemporary printed sources
- ''GRIFFITH'S VALUATION OF IRELAND'[Primary Valuation of Tenements]', 1850-1858. : Boyle Union, 6
- ORDNANCE SURVEY NAME BOOKS, County Sligo: Vol I, 409, 414
- LEET, Ambrose. ''A directory to the market towns, villages, gentlemen's seats, and other noted places in Ireland''. Dublin: Printed by B. Smith, 1814 : 125
- PARLIAMENTARY PAPERS. Return of Landowners the purchase of whose properties has been approved by Irish Land Commission. : (1889), 17.
- 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: 168
- McPARLAN, James. ''Statistical Survey of the county of Sligo'' (Dublin: Royal Dublin Society, 1802). : 9.
Modern printed sources
- BENCE-JONES, Mark. ''A Guide to Irish Country Houses''. Revised ed. London: Constable, 1988. : 89
- MONTGOMERY-MASSINGBERD, Hugh (ed). ''Burke's Irish Family Records''. London: Burke's Peerage, 1976: 755-757.
- HOWARD, Joseph Jackson and CRISP, Frederick Arthur (eds). ''Visitation of Ireland''. Baltimore: reprint by Genealogical Publishing Co. Inc., 1973: Vol VI, 64-65
- McTERNAN, John C. ''Sligo: the light of bygone days, Vol.I Houses of Sligo and associated families''. Sligo: Avena Publications, 2009. : 58-59 (Clogher), 155-156 (Old Coolavin), 300-301 (Coolavin)
- MACDERMOT, Dermot. ''Mac Dermot of Moylurg ; the story of a Connacht family''. Manorhamilton : Drumlin Publications, 1996.: All