Scale [ca. 1:144,000. 1 in. to approx. 12,000 ft.] ; 1 map : col. ; 51 x 91 cm ; Relief shown by contours and spot heights ; "Map no. 23800" ; Includes township and range grid ; Includes two profile diagrams, area and capacity curve diagram, Topography of Black Canyon and vicinity map and Colorado River basin map. Inset maps of Black Canyon and vicinity and Colorado River Basin. Inset charts of Boulder Canyon Reservoir Area and Capacity Curves; and, Profile of Colorado River from Bridge Canyon Dam Site, Arizona to Black Canyon Dam Site, Arizona-Nevada. Bureau of Reclamation.