Correspondence makes up the largest portion of these papers and includes 130 letters from her father Henry Furness about Cincinnati, Ohio politics, his reading, her work and career, family matters, and other intellectual pursuits, 1887-1911; 1077 letters and postcard from Mary Watson Whitney, her astronomy teacher and mentor at Vassar, about intellectual and professional issues, travel, affairs of friends, and other personal news, 1890-1915; 168 letters Furness wrote to her family during her student years at Vassar, 1887-1892; 174 letters received concerning Japan and Furness' efforts to aid Japanese women, 1918-1923; personal letters from Rose O'Neill, inventor of the Kewpie Doll; letters from Vilhjalmur Stefansson, Ruth E. Smith, and other astronomy colleagues regarding professional issues; letters from women colleagues discuss housing, family duties, and other difficulties in following their professional lives; and letters received about the Pan-Pacific Women's Conference, 1927. Other items include diaries from trips to Europe and Japan with records of star sightings, 1901-1928; astronomy notebooks; and memorabilia.