The first element of the name Killytoney can be either from the Irish words coill (wood) or cill (church), which are indistinguishable in anglicistions due to their pronunciation. Despite this all previous authorities including Irish language scholar John O'Donovan support the derivation from coill. O'Donovan also postulated that the second element is derived from "Tonnaig" (sic), meaning "mound" or "rampart". The Place-Names of Northern Ireland project agrees with this derivation citing that a rath formerly lay within this townland, and that a stockade may have been part of this structure or near it.
History
Population
Year
Pop.
1841
61
1851
67
1861
75
1871
68
1881
56
1891
47
1901
38
1911
40
1926
28
Size (acres, roods, poles)
Year
a, r, p
1851
207, 2, 29
1881
206, 1, 31
1901
206, 1, 31
1926
207, 2, 15
Earlier recorded forms
Year
Form
1609
Kilitvnny (E.C.)
1613
Killitomny (Charter)
1613
Kilteny
1654
Killtony
1657
Killytony
1661
Killtonney
1663
Kilty-Sonthe, Quarter of
1767
Killytoney
1813
Killtinny (S.M.)
(E.C.) - Escheated Counties Map 1609 (Charter) - Charter of Londonderry 1613 (S.M.) - Sampson's Map
^Northern Ireland Environment Agency. "NIEA Map Viewer". Archived from the original on 24 November 2011. Retrieved 27 January 2012.
^ Toner, Gregory: Place-Names of Northern Ireland, page 128-9. Queen's University of Belfast, 1996, ISBN0-85389-613-5
^ Notes on the Place Names of the Parishes and Townlands of the County of Londonderry, 1925, Alfred Moore Munn, Clerk of the Crown and Peace of the City and County of Londonderry