Kerrigan, ó Ciaragáin A Gaelic surname meaning descendant of Ciaragán (diminutive of ciar meaning ‘black’). A sept of the Ui Fiachrach, formerly seated at Baile Ui Chiaragain (Ballykerrigan) in the parish of Balla in Mayo. In north Galway it is often translated as Comber and Comer, from its supposed connection with cíor meaning a ‘comb’. In 1890 the surname was principally found in Mayo and Donegal, and the estimated number of bearers was 1,840. In the United States it is the 6,433rd most numerous surname with an estimated 5,500 bearers.