693 pp. Illustrated with 20 lithograph plates; 4 maps (2 folding), lacks loose folding map at rear. 23x14.5 cm. (9x5½"), original blind-stamped cloth, gilt spine. First Edition, Senate Issue.

One of the most widely read, popular, and influential accounts of exploration in the American West ever published. The first portion of the work reprints Frémont's report of 1843, covering his 1842 expedition to the Rocky Mountains, the second portion records his expedition of 1843-1844, delineating the major sections of the route subsequently followed by thousands of Oregon immigrants. This Senate issue contains scientific data not present in the smaller House issue. Howes F370; Wagner Camp 115; Sabin 25845; Graff 1436; Zamorano Eighty 39.