The Kate Pierce papers consist of 36 letters written to Kate, 4 school exercises, and 3 photographs, spanning 1859-1873. Kate Pierce's brother, Franklin, wrote 14 letters in the collection, describing his experiences with the 15th New York Engineers in 1864-1865. In several of these, he described his duties: on October 12, 1864, he wrote, "…our folks tore down brick houses belonging to the rebels in side of the works that we are building. You can see the avenues leading up to the cellars still remaining[.] Shrubs and bushes graveled walks all denoting that wealthy planters owned them…". He also noted his gratitude for the U.S. Christian Commission (December 24, 1864), and described a prolonged stay in the hospital, which was "warm" and a "good place to sleep" (January 12, 1865). In many letters, he requested family news and expressed pride in having a number of female penpals.
The collection also includes eight letters to Kate from Edward Brady, a musician in Company F, 13th U.S. Infantry, stationed at Fort Bridger, Wyoming. Shortly after Brady placed an advertisement requesting a penpal in a newspaper, they began corresponding. In his first letter to her (March 5, 1871), he thanked her for her "kindness in noticing my poor Advertisement (and especially from a soldier).” In his letters, Brady discussed the difficulty of educating oneself while in the army (March 5, 1871: "if one's Comrades see one improving his time by study…they would never leave off plaguing him and playing him tricks until he should quit in disgust…"). He also discussed his motivations for joining the military (March 25, 1871), described the country surrounding Fort Bridger (April 15, 1871), and recounted desertions (May 29, 1871). In his letter of July 29, 1871, Brady included two carte-de-visite photographs of himself and described a confrontation with "an Organization formed, among the Mormons for the avowed purpose of fighting against the United States in case the Law against some of there [sic] so called privileges was enforced." Correspondence from Brady ended abruptly after he asked Kate if he could write to her "as though to a sister" (December 15, 1871).
Also present in the collection are four brief compositions written by Kate Pierce: "Order of Exercise," "Imagination," "Sleigh Ride," and an untitled piece beginning "There are 'dark hours' in everyones [sic] lifetime mingled with pain and despair." All appear to date from the 1860s.