Mac Gill / Mheic an Ghaill - gall - descended from a son of the foreigner / Known as Magill in East Ulster / Also often used as an abbreviation for many of the names beginning with Mheic Giolla.

O Gillan or Gillen / Irish - Ui Giollain - giola – lad / A Heremonian Dal Cuinn Sept - Family branch of the "Northern" Ui Niaill Cenel n Eogain who had their territory in Co. Sligo - North West Connacht, Co. Donegal & Co. Tyrone - Northern Ulster / See also Gilligan & Gilliland. *88.Eogan.

Mac Gillanders / Irish - Mheic Giolla Aindreis - descended from a son of a devotee of St. Andrew / A Sept - Family branch who had their territory in Co. Monaghan - Southern Ulster / On Rathlin Island they are known as Mac Landrish / Glanders is also another variant used along with Landers.

Gillebride / Highland Scottish origins / They were in Ulster descended from the Clan Donald.

Mac Gilleece or Gillice / They were in Co. Fermanagh - South West Ulster where they were used as variants for Mac Aleese, which see.

O Gilleen / Irish - Ui Gillin / Similar to Gillen & Gillan / A Sept - Family branch who had their territory in Co. Mayo - Mid Western Connacht / Also used as a synonym for Killeen, which see.

O Gilleran / Irish - Mheic Giolla Eanain - Ui Giollarain now used / A Sept - Family branch who had their territory in Co. Roscommon - Eastern Connacht / Not connected to Gilloran.

Mac Gillereagh / A Sept - Family branch who had their territory in the Barony of Clonderlaw in Co. Clare - North West Munster / See also Gallery, Gilroy, Gilrea & Kilroy.

Mac Gillespie / Irish - Mheic Giolla Easpaig -Easpuig - easpog - bishop / descended from a son of the follower of the Bishop / A Sept - Family branch who had their territory in Co. Down - South East Ulster / Later they were in Co. Donegal - North West Ulster / Synonyms are Clusby & Glashby in Co. Louth - North East Leinster / Clasby in Co. Galway - Southern Connacht and Bishop also used.

Mac Gillian / Irish - Mheic Gileain / A Sept - Family branch who had their territory in Co. Tyrone & Co. Derry - Ulster whose origins are yet unknown.

Mac Gillick / Mheic Uilic - Uilic - William / A branch of the Anglo Irish Burkes, which see, of Connacht who are numerous in Co. Cavan - Southern Ulster .

Mac Gillicuddy / A Sept - Family branch of the Heberian Eoghancht O Sullivans, which see, who were Chiefs of the Reeks who had their territory in Co. Kerry - South West Munster / See also Gillycudy. *85.Eoghan "Mor."

Mac Gilligan / Irish - Mheic Giollagain - giolla - lad / A leading Sept - Family branch who had their territory in the north of Co. Derry - Northern Ulster where adjacent to Loch Foyle is Magilligan’s Strand / Some abbreviated to Gillan / See also Giligan.

Mac Gilligan? / A Sept - Family branch who had their territory in the Heremonian Dal Cuinn 3 Colla kingdom of Airgialla / Oriel - Southern Ulster & Co. Louth - North East Leinster.

Mac Gilligan / A Sept - Family branch who were Chiefs who had their territory in Co. Longford - North West Leinster

Mac Gillikelly / A Sept - Family branch who had their territory in Co. Galway - Southern Connacht.

Mac Gilliland / Used as a variant for Mac Lellan, which see, in Eastern - Ulster / Some shortened it to Gillan / See also Mac Gillinan.

Gillis / Scottish origins / Gaelic - Giolla Iosa / Some also used it for Mac Aleese, which see, in Ireland.

Gillman / Similar to Guillaume a French form of William / They were in Ireland in 1599 with Essex and were in the west of Co. Cork - Southern Munster.

Mac Gillooly or Gillowly / See Gilhooly.

Mac Gilloran / See Killoran.

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