The Mary Otis Preston Spafford Papers consist of correspondence, biographical information, memorabilia, and a photograph. Of particular interest are letters that Spafford wrote in 1880 and 1882-1889. The 1880 letter is addressed to her Mount Holyoke Female Seminary classmates and describes her work as "boy's attendant" at the Clarke Institute for Deaf Mutes (now the Clarke School for the Deaf) in Northampton, Massachusetts. The letters from 1882-1889 were written while she was a teacher at Huguenot Seminary in Wellington, South Africa. This correspondence is chiefly addressed to members of her family, the Prestons of South Hadley, Massachusetts. The earliest letters in the collection describe her railroad and steamship journey to South Africa by way of New Haven, New York City, and London, where she stayed at the Temperance Hotel and went signtseeing. Subsequent letters describe Huguenot Seminary, Wellington and the surrounding area, and her activities in great detail. She discusses her work as a teacher and her other duties, which included keeping financial accounts, buying supplies, and serving as acting principal. She also discusses students and other teachers, government inspections of the Seminary, the construction of new buildings at the school, and visitors, including a team of astronomers lead by Simon Newcomb of the U.S. Naval Observatory who came to South Africa in 1882 to view the transit of Venus. In addition, Spafford describes her impressions of "colored people" in South Africa, her temperance work, missionary meetings and mission work, visits to Inanda Seminary and a Zulu mission, and her summer and holiday activities, which included traveling through the country and participating in the Chautauqua Circle (a literary organization related to the Chautauqua Movement in the United States). There are occasional references to her relationship with William Swain Spafford, a gunner stationed with the British Army in South Africa whom she would marry in 1890. The final letters in the collection were written in April and May 1889. They describe her voyage to England on the S.S. Tartar and another round of sightseeing in London. A number of Mount Holyoke Female Seminary alumnae who were missionaries and teachers in South Africa are regularly mentioned in these letters, especially Anna E. Bliss and Abbie P. Ferguson (the first teachers and principals of Huguenot Seminary), M. Lizzie Cummings Gamble, Sarah E. Holbrook, Carrie E. Jannasch, and M. Emma Landfear. The letters for 1882-1889 were transcribed by Spafford's granddaughter, Ruth M. Beebe, and the transcripts, which are indexed, are part of this collection. In addition, these papers include an obituary and other biographical information about Spafford as well as a class pin and a photograph of her, both probably dating from her final year at Mount Holyoke, 1879.

This collection is organized into five series:

• Correspondence
• Transcripts of Correspondence
• Biographical Information
• Memorabilia
• Photograph