MATTHES, François E. and EVANS, Richard T. Topographic map of the Grand Canyon National Park Arizona. U.S. Geological Survey, 1927. 1060 x 940mm. Imprimé en couleurs. Map in two sheets (West and East parts), each folded in four. Fine condition. This topographic map, published by the US Geological Survey in the polyconic projection, exemplifies early efforts to accurately document the geography of Grand Canyon National Park. Produced for the 1927 edition, this detailed, large-scale map—based on surveys by Matthes and Evans—demonstrates early 20th-century precision in capturing the Grand Canyon's terrain for future use and reference. Combining polyconic projection and North American datum, the map embodies the cartographic techniques of its time, aiming to create a definitive topographic resource for navigation and geology, and reflecting evolving standards through explicit elevation adjustment instructions. As a historical document, this map offers insight into the methods of surveying and map-making during a period when such activities were critical for exploration and the subsequent development of national parks. The map’s utility lies in its ability to accurately convey the Grand Canyon's complex terrain —an essential feature for both historical and contemporary users.