Wikipedia
McGuckin is an anglicization of the Irish surname Mag Eocháin. The female form of the name in Irish is Nic Eocháin. This surname is most common in south County Londonderry followed by east Tyrone, both in Northern Ireland. The surname translates as "Son of Eocha" or "Eochán", a diminutive of the name Eochaidh. Similar to the Scottish Gaelic name Eachann. The McGuckin sept are thought to be of the Cenél nEógain of the Uí Néill.
In my McGuckin family tree, McGuckin (first seen 1853) is a corruption of the Irish name McGouchan (1827) from Leitrim, Ireland. McGouchin, in turn, is a corruption of McGuchin (c 1810), also from Leitrim. Other corruptions of McGouchin are Magoohan (1863) and McGowan (1865). The three names, McGuckin, Magoohan and McGowan, surprisingly all appear among the children of a McGouchin who emigrated from Leitrim to Scotland. The children's births were registered in Fife for the 1st child and then Edinburgh for the remainder, where all three divergent spellings were registered in random order.