Nellie Sloggett (29 December 1851, Padstow, Cornwall, UK — 1923) was an author and folklorist who wrote under the names Enys Tregarthen and Nellie Cornwall.
At 17 she suffered a devastating spinal illness and was paralysed for the rest of her life. She began to keep diaries about flowers, the changing seasons, and birds and other creatures, all observed from her bedside window. This practice eventually led to the writing and publication of her first book, Daddy Longlegs, and His White Heath Flower, in 1885 under the pen-name Nellie Cornwall.
Later she came to devote much of her attention to Cornish folklore and legend. She collected and recorded many stories about the Piskey folk, fairies of Cornish myth and legend. She published most of her works in this category under her better-known pen-name of Enys Tregarthen.
After Tregarthen's death, the writer Elizabeth Yates edited her extensive unpublished materials for publication.