1) "Sketch of Capt. Gunnison's Route to Sept. 20th 1853 Central Pacific R. Road Exploration" by Gunnison/Beckwith (20.5 x 13"). Indians killed Gunnison leaving Lt. Beckwith to complete 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, 1853, (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", by Isaac Stevens, 1853, (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 earlier versions of the maps contained in the quarto version of the Pacific Railroad Surveys and Explorations. An increasingly difficult to find set, particularly in useful condition.

References: Wheat (TMW) #861 & 842.

Condition: A

Issued folding, now all are pressed and backed with archival tissue. All with light fold toning but still very good for this series. The second map has a tiny puncture under title visible when held to the light.