This sub-series includes letters to and from members of the Hill, Williams, and DeRosier families. The DeRosier family is Ina and Eulalie Hill’s biological family. Phil, Guy, Clifford, and Lucille DeRosier are their biological siblings and they remained in close contact with each other after the Hill’s adopted Ina and Eulalie. Clifford DeRosier accompanied the Hill family on a trip to Europe in 1908.

Of note in this sub-series is the significant amount of correspondence between Frank and Abby Hill between 1887 and 1935. They were often separated for long periods of time due to Abby’s frequent and extended trips, and these letters reveal much about their relationship and activities. There are also several folders containing letters from Abby Hill to her son, Romayne Hill, from 1895 to 1897. During this period, Frank and Abby Hill were in Germany while their young son remained in the United States with relatives. The letters are particularly notable for their ink drawings by Hill.

When known, the relationship between the correspondents has been noted.