Her book for children, Chicken Little, with illustrations by Nelly Littlehale Umbstaetter, appeared in 1899;[1] as the title suggests, the book re-tells the old story of a chicken who believes the sky is falling.
As a historian Thwing compiled an enormous card index of subjects related to the history of Boston, Massachusetts.
She donated the index to the Massachusetts Historical Society, where the cards "occupied seventy-four library drawers in the catalog room.
[5] In addition to her work on Boston history she wrote about Orr's Island, Maine, where her family maintained a residence.
In the course of her life she corresponded with a number of notables including Oliver Wendell Holmes Jr., Fanny Bowditch Dixwell Holmes, Alice James, Charles Franklin Thwing, Horace Howard Furness, and Edward Everett Hale.