Recorded as Nelthorp, Nelthorpe, Nelthrop, Nelthropp, and possibly others, this is an English surname. It is locational from a place presumably spelt originally in one of the surname forms, but which has now either changed its spelling to a point where it is no longer recognized. A more likely explanation is that it has disappeared completely becoming what is known as a "lost medieval village". It is unclear how many surnames do originate from such places, but certainly in the British Isles, it runs into several thousand, over the past seven centuries. The reasons are complex. They include changes to agricultural practices, the loss of the common lands from "enclosure" by landlords, urbanisation and the drift to the towns since the end of the 17th century, civil war, plague, and ongoing coastal erosion. The place name and hence the surname is clearly Scandanavian-Viking in origin, the suffix thorp or throp being originally Danish. It described an outlying village or even a single farm away from a main centre, and probably "Njalls Farm". Many such names are from East Anglia and particularly Lincolnshire and East Yorkshire, and it is possible that the name originates from that region. Early examples of recordings include Elysabethe Neltroppe who married Harry Haryson at Christ Church, Greyfriars, in the city of London on January 18th 1551, in the reign of King Edward V1th, 1547 - 1554, known as "The Boy King", and later another Elisabeth, this time Nelthorpe, who married John Wright at St Stephans church, Coleman street, also city of London, on June 25th 1582.