The Pierce-Stuart Family papers date from 1927 to 1989 and measure 7.5 linear inches. The collection includes a series of diaries written by Mary Catherine Speece Pierce from 1927-1947, which are primarily about Harlan, Iowa. An introduction to the diaries was written by her granddaughter Mary Stuart Clark and consists of a brief biography of Pierce's life. Also included is a letter written by Pierce to her sister-in-law in 1934, charting her life experiences including the trials of traveling by covered wagon.

The diaries document Pierce's day-to-day household activities, the weather, and various community events. Included in the diaries are descriptions of her work as a deaconess in the Congregational Church, as well as efforts to establish a library in Harlan.

In addition to Pierce's diaries, the collection also contains four Pierce and related genealogies compiled by Martha Stuart Helligso and a memoir written by Mary Stuart Clark which includes accounts of early twentieth century medical crises such as fighting the flu epidemic of 1918 before antibiotics and saving a premature baby before incubators.