These are letters of William Hewson, Mary Stevenson Hewson, and Thomas Tickell Hewson, chiefly to members of the family on personal affairs. There are also a transcript of a draft of William Hewson's account of his quarrel with Dr. William Hunter and a letter from Barbeu Du Bourg to Mary Stevenson Hewson.

These are letters of Mary Stevenson Hewson to her mother-in-law, sister-in-law, and children, and their letters to her. Of special note are the letters from Thomas Tickell Hewson in London and Edinburgh. There are also letters and papers of William Hewson, including letters from Anthony Fothergill, John Morgan, and Williams Smibert, and letters about Mary Stevenson Hewson's estate. There are many references to Benjamin Franklin, Benjamin Franklin Bache, Jonathan Williams, John Hawkesworth, and others.