This map has been accorded twofold importance in the development of the westward expansion. First as a major contribution to geographical and cartographical knowledge and secondly, as historic documentation of Fremont's third expedition. The map is a remarkable graphic depiction of this expedition and is considered one of the most important 19th century American maps. It covers all of the western territories from the 105th Meridian. Among the most interesting features are the appearance of the term Golden Gate at the entrance to the Bay of San Francisco, the markings of the El Dorado or Gold Region in the California Gold Fields, a hypothetical east-west mountain range near the 42nd parallel, and a notation identifying the location of Mormon settlements for the first time. Wheat illustrates the map and devotes eight pages to its description.

Having been court-marshaled and dismissed from the Army in 1847, Fremont was not asked to publish the details of this last expedition by the Corps of Topographical Engineers as would normally be required. Instead, the Geographical Memoir comprised his report. It was published nonetheless by Congress at the behest of the powerful Senator Thomas Hart Benton, Fremont's father-in-law. The memoir is also known as Misc. Doc. No. 148, 30th Congress, 1st Session. This is the large, and increasingly rare, map from that report.

References: Wheat (TMW) #559; Wheat (Gold) #40; Goss (NA) #77; Schwartz & Ehrenberg plt. 171

Condition: B+

A nice example, issued folding, with no tears or separations. Light toning primarily along the folds with a few small faint damp stains at fold intersections. There are a few minor extraneous creases at left from where the map was bound in the report.