Sloan, Sloane, ó Sluaghadháin Both an Irish and a Scottish surname derived from Sluaghadhach meaning ‘fit for hoasting’ (in the military sence). In Scotland a sept of Galloway. In Ireland a sept of Mayo. In 1890 Sloan was principally found in Antrim, and the estimated number of bearers was 2,730. In the United States Sloan is the 665th most numerous surname with an estimated 49,500 bearers.