The papers consist of correspondence, writings, personal papers, legal and financial records, and related papers of the De Forest family. There is also some correspondence relating to the Sergeant and Shepard families (who married into the De Forest family). Family members prominent in the papers include John Hancock De Forest, his wife Dotha Woodward, and their sons George Frederick De Forest, Henry Alfred De Forest, Andrew Woodward De Forest, and John William De Forest. John Hancock De Forest's brothers, Benjamin and Ezra De Forest, and their children are also represented in the papers.
Drafts and printed material by and relating to John William De Forest provide insight into his writing career. De Forest's career is similarly reflected in contracts and correspondence with publishers. The Writings series also includes his son Louis Shepard De Forest's book Tuberculosis as a local and contagious disease in New Haven (1891).
Family papers contain business and genealogy documents. Warranty deeds, wills, and estate documents trace the De Forest's wealth and connection to Connecticut history. A number of warranty deeds reflect the De Forest's acquisition of property in Seymour, Derby, and New Haven, Connecticut. Some legal and financial records relate to John Hancock De Forest's company, the Humphreysville Manufacturing Company, and Seymour (formerly Humphreysville), Connecticut. An inventory of Dotha Woodward De Forest's estate following her death lists the contents of the De Forest's home, such as furniture, books, clothing, and other household effects, which combined provide insight into the life of a Connecticut family in the mid-nineteenth century. Military papers and a passport for John William De Forest document his experience as a soldier. The Family Papers series also includes documents pertaining to the histories of the De Forest, Sergeant, and Shepard families.