A clan closely identified with the Uí Cléirigh surname is the McCleary name. There are several possible sources for this name. One could suppose that it is derived from the Gaelic Mac Cléireach son of the Cleric or Clerk. However the name has a completely different origin derived from the personal name Mac Giolla Arraith “ son of the servant of Arraith” or as Patrick Woulfe suggests Mac Giolla an Raith.’son of the prosperous youth’. It is difficult to determine the precise origins of the surname and there are possibly two areas in Ireland were the surname comes from. The first is the name Mac Giolla an Raith which was anglicised as McCleary with origins in County Sligo which does not seem to be very numerous.
Today the McCleary name is mainly found in Ulster and in Griffith’s valuation of 1862 in County Antrim there were 36 ratepayers with the surname in Co. Londonderry/Derry 15, in Co. Down, 8 and in Co Donegal,13. Other northern counties have smaller numbers.
As you can see in the accompanying map of the baronies of County Antrim the name is mainly concentrated in the southern part of the county. However in the 1659 survey of Co Antrim the name is not recorded at all but in the East Donegal Muster Roll 1630-1631 there is one Michael McCleary living on the estate of William Steward Esq. Laird of Dunduff and is recorded as being in possession of Sword or Snaphance (the latter being a is a type of lock for firing a gun or is a gun using that mechanism) The district of Dunduff is in South Ayrshire.
The other and most likely origin for most of the McClearys of Ulster is across the sea to Scotland where the name is recorded as early as 1376 where one Johan M’Cleri is recorded in the Ancient Charters of the Earldom of Morton during the reign of King Robert II (1371-1390) James Douglas (1426 – 22 October 1493), the 4th Lord of Dalkeith, was created the 1st Earl of Morton in 1458. The lands of Whittinghame and all rights over the barony of Morton, Dumfriesshire were resigned into the Earl’s hands in 1473-4 and in that same year he recovered the lordship of Dalkeith increasing the Earls already vast estates.[
Ernhanane Clouyncude
Affedantur M’Cleri adterminumun iusanni pro XVI plegio Cudberto M’Narne
The Ernhanane and Clouyncude refer to lands being leased for the term one year by (Johan)M’Cleri with a pledge from Cuthbert Mc Nairn but cannot say where these lands were situated. The Earls of Morton had lands in Fife and Lanark and it seems that the title itself originates from Morton in Lothian. In the 1841 Census of Scotland there are many families of McChlery in the counties of Wigtownshire, Kirkcudbrightshire and Dumfriesshire. All these counties are close to Co Antrim and one can see how over a period of time many crossed the sea to Ireland settling in the northern parts of Ulster.
As a footnote, the Scottish Mc Chlerys surname does come from the Gáidlig Mac an Chleireach “son of the Cleric” see The Surnames of Scotland (1946) by George Fraser Black (1866-1948) See: https://babel.hathitrust.org/cgi/pt?id=mdp.39015011274175&view=1up&seq=556
This map shows the location of those with the McCleary name in the 1901 Census. Anyone interested in this map and that of other surnames look at the website : https://www.barrygriffin.com/surname-maps/surnames.php?surname=McClea