Long, Longaigh The Gaelic surname Longaigh, derived from long for a ship, a camp. A sept of Muskerry, they were an erenagh family based in the parish of Cannaway in Cork. An English surname either descriptive, or a nickname. Also of Norman origin: de Long. In 1890 Long was principally found in Cork, Dublin, Limerick, Kerry and Donegal, and the estimated number of bearers was 4,070. In the United States it is the 86th most numerous surname with an estimated 253,000 bearers.