Madden, ó Madáin A Gaelic surname meaning descendant of Madadhán, diminutive of Madadh, meaning ‘a dog’. A sept of the Uí Mhaine, whose territory consisted of the barony of Longford in Galway and the parish of Lusnagh in Offaly. ó Maddegane in Antrim were a separate family. In 1890 Madden was principally found in Galway, Cork, Dublin and Antrim, and the estimated number of bearers was 4,790. In the United States it is the 943rd most numerous surname with an estimated 35,750 bearers.