This collection consists of correspondence from contractors William Miller and William Patterson dating from 1864 to 1888. It relates to their involvement in the construction of the Union Pacific section of the transcontinental railroad, mainly in Wyoming along the Green River and in Echo Canyon, Utah. Included are letters regarding supplies for the work camp, competition among builders for contracts, and interactions with The Latter-day Saints Church, among other topics. It also includes letters written between Miller and Patterson after the end of their partnership. Notable among the correspondence is a copy of a letter written by William Patterson to Brigham Young asking for a copy of the church leader's contract with the Union Pacific Railroad.