This popular Ulster name is most common in counties Antrim and Armagh and can be of Irish, Scottish or English origin, In England the name, originally Hamel, derives from the Old English word hamel, meaning ''scarred' or 'mutilated'.

In Scotland the name is of Norman territorial origin.  The first of the name on record there was William de Hameville in thirteenth-century Annandale in Dumfriesshire.  The name is well recorded in Lothian but was most common in Ayrshire and indeed, Hugh Hammill of Roughwood in Ayrshire was one of those who accompanied Montgomery of the Ards to Ulster.

However, already in Ulster at that time, the O'Hamills, Gaelic Ó hAghmaill, were one of the leading septs of the Cenél Binnigh, a brianch of the Cenél Eoghain.  As such the O'Hamills claim descent from Binneach, son of Eoghan, son of the fifth-century Niall of the Nine Hostages, founder of the Uí Néill dynasty.  The O'Hamills ruled a territory in south Tyrone and Armagh and from the twelfth century were poets and ollovs (learned men) to the powerful O'Hanlons.  By the seventeenth century the name was most numerous in Armagh and Monaghan and by 1900 was also common in Louth.  The prefix O' is now used only in Co. Derry, and there rarely.  The name has also been made Hamilton in that Country and elsewhere.



Clan From the Gaelic clann which means literally 'children'.
Mac- From the Gaelic mac, meaning 'son'
O' From the Gaelic Ó, meaning 'grandson', 'grandchild' or 'descendant'; Ní is the femine form of Ó, meaning 'daughter' or 'descendant'
Plantation (Ulster) The redistribution of escheated lands after the defeat of the Ulster Gaelic lords and the 'Flight of the Earls' in 1607.  Only counties Donegal, Derry, Tyrone, Armagh, Fermanagh and Cavan were actually 'planted', portions of land there being distributed to English and Scottish families on their lands and for the building of bawns.
Sept A family group of shared ancestry living in the same locality
Undertakers Powerful English or Scottish landowners who undertook the plantation of British settlers on the lands they were granted.
Gaelic This word in Ireland has no relation to Scotland.  As a noun it is used to denote the Irish language, as an adjective to denote native Irish as opposed to Norman or English origin.
Erenagh From the Irish Gaelic airchinneach, meaning 'hereditary steward of church lands'.  A family would hold the ecclesiastical office and the right to the church or monastery lands, the incumbent at any one time being the erenagh.