De Rosfort

de ROSFORT—XI—de Rochefort, de Rocheford, de Rochford, Rochefort, Rochfort, Rochford, Rushford, etc.; Norman 'de Rochefort,' Latin 'de Rupe forti,' i.e., of Rochefort (strong or fortified rock) in France. This surname came into Ireland at the time of the Anglo-Norman invasion and soon became very widespread. In the 16th century, it was found chiefly in Meath, Westmeath, Kildare, Carlow, Wexford, Waterford and Limerick. It is now, strange to say, comparatively rare. In Limerick, the Irish forms Rostard and Rostún (which see) are found.

Alphabetical Index to Irish Surnames