The Charles William Merrill papers contains correspondence to and from his family during his time as a soldier in the American Civil War. The collection also contains letters written to his father, William Merrill, regarding the wounding and subsequent death of his son. Additionally, the Bible that Merrill was wearing at the time of his wounding, with the bullet, and a replacement Bible signed by President Lincoln are included. Miscellaneous items included in the collection are a photograph of Merrill; transcriptions of some of the letters completed by David Little, as well as articles written by Little.

Some of Elizabeth T. Merrill's correspondence was burned when her bureau caught fire, and is missing pieces of it. A roll of recruits is included in the correspondence in box 1, folder 1.