This is a Cornish locational surname of post medieval origins. The name means "the valley of the deer" or similar, from the pre 7th century Olde English and Cornish-Breton "nans carow". Locational surnames were usually "from" names, which is to say that they were given to people after they left their original homes, for whatever reason, and moved elsewhere. "Elsewhere" could be the next village, which seems to be generally the case in Cornwall, although in other parts of the United Kingdom, it could, and often was, as far away as London. Nethertheless the same principle applied that the easiest way to identify a "stranger" was to call him or her, by the name of the place from whence they came. Local dialects being thick, and spelling being at best erratic, often lead to the development of many and sometimes colourful forms, some barely recognizeable. In this case early examples of the surname recordings taken from surviving church registers includes Vrias Nancarrow of St Emoder, on May 8th 1598, and Ann Nancarrow who married William Rogers at Constantine, on February 27th 1777. The earliest church recording is believed to be that of Agnes Nancarrowe, the daughter of Hugo Nancarrowe, christened at Wendrow, Cornwall, on November 6th 1577. This was during the reign of Queen Elizabeth 1st, 1558 - 1603.