Nelson, Neilson A Scottish surname, meaning son of Niall. The Neilsons of Craigcaffie are said to trace their descent form Niall, Earl of Carrick, husband of Margaret Stewart who died in 1256. Also an English surname. In 1890 Nelson was principally found in Antrim, Down, Derry and Tyrone, and the estimated number of bearers was 3,225. In the United States Nelson is the 39th most numerous surname with an estimated 445,500 bearers. In England and Wales in 1996 it was the 238th most numerous surname.