The materials in this collection come originally from the estate of Julia Osgood (d. 1908), John Cleveland Osgood's sister, who served as the family's unofficial historian and genealogist. When she died, her nephew Charles Russell Osgood (1875-1967), son of Julia's other brother Charles Edward Osgood (1845-1899), inherited the material. The collection was then passed down to Charles Russell Osgood's daughter, Charlotte Blackmer (b. 1918).