The largest part of the John Henry Barker collection consists of 45 letters, 44 written by Barker to his sister Jenny over the period of 1871 to 1890. The other letter was written to Jenny by George Teasdale, her future husband. Twenty-two of these letters were published by the Daughters of the Utah Pioneers in their Historical Pamphlet for October 1960 as "Letters of John H. Barker" (F 826. D32). This publication also includes three other letters not included in this collection: those of January 20 and January 22, 1881; and June 17, 1888 – the last being Mr. Barker's admission to his sister that he was practicing plural marriage.

The Barker collection contains a vast amount of information about the life of an early settler in Utah. Barker writes with great detail about his jobs, his family and home life, and his community. He comments on everything from politics to religion to the weather. His letters urging his sister to come to Utah and join him are full of details about what she can expect from the trip and what the trip was like when he made it. It is interesting to note that even small details, such as the price of goods and the amount of his wages are given.

The letters are organized chronologically from November 16, 1871 to the last letter written in 1890. In addition to the letters, this collection also includes several interesting documents and artifacts. Envelopes and stamps from some of the letters have been preserved. The collection also contains tickets for the passage from England to America for both Barker and Susan Dermott, their marriage certificate, LDS family group record sheets, and several photos. The last item is a diary kept by Barker from May 9 1859 to March 1863. All of these items are organized and preserved in folders following those containing the letters.