 The 1790 Cavan Carvaghs list spells the name as "Kilullin".A map dated of the townland dated April 1794 is held in The County Cavan Archives (ref P017/0025).The description is-

"Map of Killywilly (Killawilla or Killwilly), part of Ballymagauran, 'the coppy, and the commons,' held by Lancelot Slack from the Right Honourable Marquis of Waterford.