Harkness spent much of her life traveling throughout the continent working and writing for various jobs and magazine or newspaper companies. She came back to London to be with her mother while she was ill. Once her mother passed away, Harkness traveled back to the continent. Two years after the publication of her last novel Harkness died at the Pensione Castagnoli in Florence on 10 December 1923. She was buried the next day at a local cemetery. She was identified on her death certificate as a spinster of independent means. 

“Margaret Harkness (1854-1923).” Victorian Secrets, Victorian Secrets Limited, 15 Sept. 2015, https://victoriansecrets.co.uk/authors/margaret-harkness/. 

Harkness, Margaret. A City Girl, edited Tabitha Sparks. Broadview editions 1887.