Relief shown by hachures and spot heights. Prime meridian: Washington. Shows exploration routes, state borders. At lower left: "Issued Feb. 4th, 1878." "By order of the honorable, the Secretary of War, under the direction of Brig. Gen. A.A. Humphreys, Chief of Engineers, U.S. Army." Includes table of "dates of camps of river party in 1871." 1 map: 37 x 45 cm.