Maps: Their Use by Overlanders

Scott Eldredge, Digital Project Manager
Harold B. Lee Library, Brigham Young University

It is important to realize that most emigrants leaving their homes to follow pioneer trails did not march off into the west entirely ignorant of the country that lay before them. The diarists in this digital publication often demonstrate considerable planning for their overland experiences, from the outfitting stage to the selection of a company and leader. Undoubtedly many emigrants expected their leaders to have all of the trail knowledge that would be needed. Brigham Young demonstrated the expected leadership quality when he requested six copies of Mitchell’s “New Map of Texas, Oregon and California”[1] before beginning the now famous Mormon Pioneer trek of 1847 which led to the establishment of Salt Lake City and the subsequent state of Deseret.[2]

Even if the traveler was not familiar with the geography of their impending trail experience, by the beginning of the 1840’s, when overland travel to the Rockies and the pacific coast began in earnest, much was known about this vast area. Large holes existed in contemporary western geographic knowledge, but most of the areas traversed by the travelers along the major emigrant trails were known and mapped for several decades through government explorations and private enterprise. Lewis and Clark, Zebulon Pike and Stephen H. Long all led early expeditions covering parts of future emigrant trails. Trade and commerce also spurred private forays such as the Astorians, and three decades of traders, trappers and mountain men filled in many of the earlier gaps as their supply trains forged the trails to Oregon and California. For all of these groups, success, and often their survival, directly depended on the accuracy of geographical information. Collecting and sharing knowledge of the river systems, the mountains and their passes was so important that many of these early travelers drew their own maps, while others contributed information to professional cartographers. By the end of the 1830’s a variety of maps were available to emigrants, sometimes included in trail guidesor often published in popular and readily available atlases. The sources of the information found on the maps can be organized into general categories.[3]

Government Exploration

The “Map of Lewis & Clark's track across the western portion of North America”[4] was published in 1814. Long’s widely available map, “Country Drained by the Mississippi Western Section,”[5] had a lasting impact on emigration patterns due to it’s labeling of the central and southern plains as the “Great American Desert.” Later government exploration was largely driven by the increase in emigrant traffic. By the early 1840s exploration of the west was being carried out under the direction of the U. S. Corps of Topographical Engineers. Expeditions such as John C. Fremont’swere particularly significant since their advent marked the first time that scientific methods were applied to charting the region. Subsequent government expeditions were carried out regularly through the 1840s, 50s and 60s and were headed up by men such as John Wilkes, Ferdinand Hayden, William Raynolds and Howard Stansbury.[6]

Commercial Enterprise

Early government exploration spawned waves of commercial ventures aimed at exploiting the vast resources of the west. In 1811 John Jacob Astor sent an expedition overland to the Pacific and back. Their routes are outlined in the map: “Sketch of the Routes of Hunt and Stuart.” For three decades trappers and traders made their way up the Missouri River and eventually overland to the Rocky Mountains in search of furs. Although few of these adventures led to published maps, many of these men served later as emigrant guides and much of their geographic knowledge found its way into contemporary atlases.[7]


Many emigrants also contributed geographic data that resulted in new maps. Samuel Parker’s ”Map of Oregon Territory”[8] is an excellent example. Others were to be found in the variety of trail guides published for the use of emigrants. William Clayton’s “The Latter-day Saints' emigrants' guide” although published with Mormon emigrants in mind, was also quite valuable to Oregon and California bound groups. Unruh even went so far as to call it “one of the most reliable and highly praised of all gold rush guidebooks.”[9]

Over the course of the major years of emigration along the pioneer trails there was a natural increase in the breadth and depth of published geographical information and the emigrants in the latter years of the pioneer era enjoyed the advantage of more in-depth and accurate data. This greater store of knowledge was contributed by the emigrants themselves and was greatly enhanced by the launch of numerous government surveys.

Although more information became available to emigrants over the years, other circumstances reduced somewhat the need for that data. By the late 1850s the trail, from various jumping off places along the Missouri River to South Pass in present day Wyoming, was so well established that it would have been difficult to lose ones way. Also, many people had begun to settle along the trail, often offering goods and services to the emigrants. By that time, emigrants rarely traveled more than one or two days without encountering at least one habitation.[10] Mormon diarist, John Peter Rasmus Johnson, traveling in the summer of 1864 along the Platte, repeatedly wrote about camping at various ranches, for example, “Carter’s ranch” or “South Platte ranch” or “Grove’s ranch.”[11]

Multiple Sources

Although these categories are useful in identifying the origins of geographical data, it is helpful to note that many of the published maps were based on data from a combination of sources. Early government charts often included information gathered from traders or others engaged in private enterprise. Many atlases used government maps as a basis, but included additional information from other sources. The Arrowsmith Map of 1834, for example, contains information gathered by the British-owned Hudson’s Bay Company’s Snake Country Expeditions from 1824 to 1830 under John Work as well as some data that likely originated from American operations under the direction of William H. Ashley in the mid 1820s.[12] Often maps or atlases contained information harvested from trail guides and most trail guides also included maps.


The 43 maps in this collection represent only a small sampling of those that were available to emigrants during the overland trails period of 1847 – 1869. Carl I. Wheat’s Mapping the Transmississippi West, 1540-1862 was used as the primary guide for selecting maps for this digital publication. In addition, we relied on the works of Stanley B. Kimball to assist us in our selection of the maps that were studied and used by Mormon emigrants and their company leaders.[13] For additional map sources see the “Atlases and Maps: section of the “Selected Readings” list found as a part of this digital publication.


  • 1. S. Augustus Mitchell, A new map of Texas, Oregon, and California: with the regions adjoining  (Philadelphia: Mitchell. 1846, c1845).
  • 2. Carl I Wheat, Mapping the Transmississippi West, 1540-18, vol. 3 (San Francisco: The Institute of Historical Cartography, 1958),31.
  • 3. Ibid, vols. 2 & 3.
  • 4. “Map of Lewis & Clark's track across the western portion of North America,” in History of the expedition under the command of Captains Lewis and Clark : to the sources of the Missouri, thence across the Rocky Mountains and down the river Columbia to the Pacific Ocean : performed during the years 1804-5-6, vol. 1 ( Philadelphia: Bradford and Insskeep, 1814).
  • 5. “Country drained by the Mississippi western section,” in Account of an expedition from Pittsburgh to the Rocky Mountains : performed in the years 1819 and '20 by the order of the Hon. J. C. Calhoun, Sec'y of War, under the command of Major Stephen H. Long, comp., Edwin James (Philadelphia: H. C. Carey and I. Lea, 1823).
  • 6. Ferdinand V. Hayden, First, second, and third annual reports of the United States Geological Survey of the territories : for the years 1867, 1868, 186 (Washington: Govt  Print.Off., 1873); W. F. Raynolds, Report of the exploration of the Yellowstone River (Washington : Govt. Print. Off., 1868); Howard Stansbury, Exploration and survey of the Valley of the Great Salt Lake of Utah : including a reconnoissance of a new route through the Rocky Mountains (Washington : Robert Armstrong, Public Printer, 1853); Charles Wilkes, Narrative of the United States Exploring Expedition during the years 1838, 1839, 1840, 1841, 1842 (Philadelphia, Printed by C. Sherman, 1844).
  • 7. Fred R. Gowans, Rocky Mountain Rendezvous  (Layton, Utah: Peregrine Smith, 1985); Reuben Gold Thwaites, Early Western Travels, 1748-1846, 32 vols. (Cleveland: The Arthur H. Clark Company, 1904);John D. Unruh Jr. The Plains Across: The Overland Emigrants and the Trans-Mississippi West, 1840-60  (Urbana: University of Illinois Press, 1979); Henry R. Wagner and Charles Camp, The Plains and Rockies: A critical bibliography of exploration, adventure and travel in the American West, 1800-1865, ed. Robert H. Becker, 4th ed. (San Francisco: John Howell Books, 1982).
  • 8. Samuel Parker, “Map of Oregon Territory” in Journal of an exploring tour beyond the Rocky Mountains, under the direction of A. B. C. F. M., in the years 1835, '36, and '37 (Ithaca, NY: Mack, Andrus & Woodruff, 1842).
  • 9. William Clayton, The Latter-day Saints' emigrants' guide: being a table of distances, showing all the springs, creeks, rivers, hills, mountains, camping places, and all other notable places, from Council Bluffs, to the valley of the Great Salt Lake (St. Louis, Mo. : Republican Steam Power Press - Chambers & Knapp, 1848); Unruh, 317.
  • 10. Unruh., 379-81.
  • 11. John Peter Rasmus, July 28, 1864, p. 2; July 29, 1864, p. 2; July 30, 1864, p. 2.
  • 12. Wheat, vol. 2, 146-8.
  • 13. Stanley B. Kimball, Historic Resource Study: Mormon Pioneer National Historic Trail (Washington D. C.: U.S. National Park Service, Department of the Interior, 1991), 31-32.