During the 1850s, the U.S. government sponsored an extensive series of expeditions designed to gather information on the vast new territories that had been acquired in western North America. The discovery of gold in California further stimulated westward traffic and heightened the need for a faster and more convenient way to bring the far-flung parts of the country together. In 1853 Congress commissioned the Army's Topographic Bureau to conduct a series of surveys to find a suitable route for a transcontinental railroad. There were six major expeditions; five of them covered the area between the Great Plains and west coast, and the sixth explored the coastal states of California and Oregon. All of these expeditions were accompanied by naturalists and artists to document the landscape, flora and fauna along the route. The reports, maps and lithographs were published in the 13 volume report "Explorations and Surveys to ascertain the most practicable and economical route for a Railroad from the Mississippi river to the Pacific Ocean."

1) Sketch of Capt. Gunnison's Route to Sept. 20th 1853 Central Pacific Rail Road Exploration, (20.5 x 13"). Indians killed Gunnison and Lt. Beckwith before they completed the survey. This is a great early map of present-day Colorado. It depicts several exploratory routes in the Rocky Mts. 2) Sketch of the Northern Pacific Rail Road Exploration from St. Paul to Fort Union, by Isaac Stevens, (32 x 17"). This map shows Stevens' route and the route of Lt. Grover from Pike Lake to Ft. Union. 3) Sketch of the progress of the Northern Pacific Rail Road Exploration up to the crossing of the Shayen River. July 4th, 1853, by Isaac Stevens,(25 x 15.5"). Includes a lower route from White Bear Lake to Shayen, the Red River Trail. Wheat notes that these three maps are the less common, earlier versions of the maps contained in the quarto version of the Pacific Railroad Surveys and Explorations.

References: Wheat (TMW) #861 & 842.

Condition: B

Issued folding, now all backed with archival tissue. Numbers 1 & 2 with very light fold toning, number 3 is toned on folds & offset.