In 1849, officials of the US Army Corps of Topographical Engineers sent Captain Howard Stansbury and his assistant Liuetenant John Williams Gunnison on a two-year expedition to explore and survey the Great Salt Lake Valley. While the area was not unknown — indeed a major influx of Mormon settlers had already taken place — the the end of the end of the Mexican-America War in 1848 and the massive new western areas gained by the United States, spurned a new era of scientific mapping there.
Thus it was that in May 1849, Stansbury, Gunnison, and a small team set out for the Great Salt Lake from Fort Leavenworth, Kansas. Along the way, they accumulated the cartographic data that would form the basis for this map, a remarkable scientific achievement. It intricately maps parts of the Missouri, Kansas, and Arkansas rivers. From east to west, it extends from the edge of modern-day Kansas City, past modern-day Denver, and on to the emerging Salt Lake City.
The map is considered to be the first accurate survey of the Great Basin and the southern Rocky Mountains, and was especially important in identifying a new, shorter route to the Salt Lake through Bridger’s Pass and Cheyenne Pass. The route, carefully recorded in exceptional detail, had an enduring impact; the Overland Stage, Pony Express, and Union Pacific, would all make use of it.
A cornerstone map for the history of cartography in the emerging American West.