Save Type Surname (from location) Usage Cornish Other Forms FormsTregarthan, Tregarthyn Meaning & History From Tregarthen in Ludgvan; from treg-ar-den the dwelling upon the hill, or treg-arth-en, the dwelling upon the high place.Used by Cornish author and folklorist Nellie Sloggett (AKA Nellie Cornwall) as one of her pen-names.