This primary source comes from the Records of the Office of the Chief of Engineers.
Full Citation: Map of Survey from Salt Lake City to Humbolt Wells; 2/4/1869; Roads; Civil Works Map File, 1818 - 1947; Records of the Office of the Chief of Engineers, Record Group 77; National Archives at College Park, College Park, MD. [Online Version, https://www.docsteach.org/documents/document/map-of-survey-from-salt-lake-city-to-humbolt-wells, April 24, 2025]