After breaking her wrist in her seventies, Terhune learned to use a typewriter. In her 90s, she went blind, but continued work by dictating to a secretary. Her final work, the novel "The Carringtons of High Hill", was published in 1919. Terhune continued creating articles and essays until she died on June 2, 1922. Over her life, she published 25 novels, 25 non-fiction works on homemaking and cooking, three short story collections, several biographies, travel guides and histories, and numerous essays, articles, and serial works. Two of her children, Christine Terhune Herrick and Albert Payson Terhune, became noted writers as well, with Herrick following in her mother's footsteps as an authority of domestic matters, and Albert Terhune becoming notable for his novels featuring collies. Her middle child, Virginia Van de Water, also became a writer, though less well known. Late in life, Mary Terhune co-wrote works with each of them.