Gortmullan is a townland in the Civil Parish of Tomregan, Barony of Knockninny, County Fermanagh, Northern Ireland.
The townland name is an anglicisation of the Gaelic placename “Gort Mhaoláin” which means ‘Maolán's Field’. It might also mean ‘The Field of the Mill’. The oldest surviving mention of the name is in a grant dated 14 October 1612 where it is spelled ‘Gortmonylan’. Spellings in later grants are 1629- Gartmolan and 1659 –Gorttmoylan.
It is bounded on the north & west by Knockateggal townland, on the east by Ummera & Gortineddan townlands and on the south by the international border with County Cavan and the Republic of Ireland. Its chief geographical feature is Slieve Rushen mountain on whose eastern slope it lies reaching to an altitude of 270 metres above sea-level.
The townland is traversed by the Border Road to Ballyconnell and some minor lanes.
Gortmullan covers an area of 315 statute acres.
The townland formed part of the ballybethagh of Calvagh in medieval times. At the beginning of the 17th century it was owned jointly by Bryan McPhilip O’Reyly and Edward Rutlidge but was confiscated by the Crown in the 1609 Ulster Plantation and it formed part of the half-territory of Aughrin which was granted to Sir Hugh Culme in 1610. Culme later relinquished his claim to the Crown, perhaps because there was confusion at the time as to whether the townland formed part of County Fermanagh or County Cavan. By an order of the Lord Deputy dated 14 October 1612 the townland was granted, inter alia, to Lady Margaret O’Neill, the widow of Sir Hugh Maguire deceased. An Inquisition held at Newtownbutler on 20 January 1629 found that Thomas Duffe McCorie was seized of the lands of, interalia, Gartmolan. In 1641 and also in 1670 it was owned by Sir William Balfour (general).