Mooney, ó Maonaigh
A Gaelic surname meaning descendant of Maonach, meaning ‘wealthy’ according to Woulfe. A sept who were chiefs of Clann Murthuile in Roscommon. A sept of the Uí Fiachrach, whose territory was south of Sligo bay in the barony of Tireragh. A sept of the Siol nAnmchadha, in the south east of Galway. In 1890 Mooney was numerous in Offaly, it was also to be found in Dublin and Antrim. The estimated number of bearers was 6,092. In the United States it is the 904th most numerous surname with an estimated 35,750 bearers.