second most numerous name in Ireland: in every part, especially Connacht. Irish is Ó Ceallaigh, Ceallach, bright-headed, a very old first name. The leading sept was of the Uí Maine in Galway. Now usually appears as O'Kelly. IF, SGG & GPN.
Kelly: ní féidir idirdhealú ar Ó Ceallaigh. Bhí Mac Ceallaigh i nGailimh in anallód ach baineann an sloinne seo go príomhdha le Oileán Mhanann.
numerous: all areas, especially N Munster. Ir. Ó Ceallaigh. Perhaps from ceallach, frequenting churches, but more likely an older name connoting "bright-headed". (GPN). The most important family were chiefs of Uí Maine (E Galway). There were a number of other septs in places such as Derry, Wicklow, Laois and Cork. See also Kelly. SGG.