The Irish surname MacManus, also found in Scotland, is an anglicized form of the Gaelic name Mac Maghnuis, patronymic from a Gaelic form of the Scandinavian personal name Magnus. As an Irish name this is found chiefly in counties Roscommon and Fermanagh and is connected with the O’Connors and the Maguires; in Scotland it is connected with the Colquhouns. The first recorded spelling of the family name is shown to be that of Hugh McManus, (marriage to Mary Gawin), which was dated 1662 at Derry Cathedral.Today the name is found most frequently in counties Cavan, Fermanagh and Roscommon.