The John Peirce Papers consists of letters written by Peirce to his wife, Clarissa Williams (1888- ), and sons John and Clarence. His letters describe camp life in various forts around Washington, DC, describe his duties as an ordnance handler (particularly artillery) and comment on the events of the day. His letters include descriptions of the regiment's living quarters, the daily routine, the number and contents of the meals provided to the soldiers, and the prices charged for local produce with which the soldiers sought to supplement their rations. Major locations where Peirce was stationed include: Forts Pickering and Lee, Salem, MA; Forts Snyder, Ricketts, Reno, Thayer, Saratoga, and Lincoln – all in the Washington, DC area.

Peirce's letters to Clarissa include news of current events in Washington, DC, victories in battle, the surrender of Lee, and the capture of Jefferson Davis. His letter written on April 15, 1865, after the assassination of President Lincoln, describes the alarms, the actions taken in the forts, and the feelings of the soldiers on hearing of Lincoln's death.

Letters to Peirce's sons describe sights which would interest young boys, such as the long trains bearing soldiers to the front, mule trains, cavalry on parade, military bands, as well as fishing, small game hunting, and collecting berries in the areas around the forts. Included in Folder 3 is a sketch of an officer, complete with sword, which John drew for his younger son, Clarence.

Folder 4 contains transcriptions of all of the letters done by Frances Malamy in 2005.